Audience response system and data transfer protocol

the Invention relates to a method and an apparatus for interrogating or Collecting user responses to a base unit which in individual remote response units are entered. The invention is particularly suitable for individual responses of listeners to them asked to acquire question. The invention is as an educational aid in determining the perception of students in a class and apply as a commercial means for directing of listener polls and the same. The invention, even for long-distance orders in restaurants, find merchandise trade traffic and the like application.

It There has long been a need for an immediate feedback from listeners to get to them asked question. In a lecture may wish the audience one of the speakers, for example, to ask question, to monitor the level of understanding. If the reaction of the class indicates a high level of understanding, the speaker may proceed with a new material. If understanding to is low, a repeat can be displayed. In another Application, a marketing plan the presentation of various Include options to a test audience and contain an immediate vote of the audience to certain preferences for different Packaging designs, logos, advertisements and determine the like.

It are two basic Types of response systems: wired, units in which the remote are connected by conductors with a base unit and wireless. While the wired systems more options for the design of the circuit offer to allow rapid collection of the responses, is a permanent installation of the lines in a given space often not possible and connected to high installation costs. The wireless system however, is flexible in terms of use in various occasions and is arbitrarily movable. However, the fact that wireless system Transmit signals to communicate, limits the options of a system design. As a result, the response speed is impaired, what to leads, that when conventional wireless Response systems collecting the responses or answers to slow takes place, especially if the system has a large number of remote response units, for example, 250 contains. It should also the number of functions is limited in a wireless system.

The <patcit><text>US Patent 5,093,786</text></patcit> disclosed a wireless remote response system in which a base unit address words to remote response units transfers. identifies each response unit an address word that belongs to that particular response unit and transmits a Response that is entered by the user, to the base unit in response to identification of its address word. The base unit determines that a valid Word of the response unit is received and sends a confirmation message. The remote response unit assumes a first mode or status at the entrance to a reply by a user. The remote Response unit moves continues to transmit a data message, when it receives its own address word to the central control unit an acknowledgment message to be transferred Response unit transmits. At the Receiving the acknowledgment message change the remote response unit in a second resting Status or mode. While such a system reliable and is fast, it still has drawbacks. To address words quickly and reliable to transmit from the base unit to the response units, as well as response data from standardize the response units to the basic input, two communication channels, the operate at different frequencies, are used so that the communication at the same time from the base unit to the remote response units with the communication from the remote response units to the can be carried out base unit. require differentiated communication channels However, an increased Bandwidth and are not available in all cities. In addition, the data format in my patent rigid and no longer used as an answer mark by the user. Therefore, it is limited to a reply with Yes / No and multiple choice questions.

the <patcit><text>DE 43 21 801</text></patcit> discloses a Apparatus for wireless connection of responses of multiple Users. Question signals are sent to response units which the units are to elicit a response, in which the user has entered a particular code or number. On Thus, the base station can determine the number of replies, by measuring the energy or power of the response signals after transfer each of question signals are received. There is no disclosure a base data packet that consists of a plurality of characters, of which at least a portion is directed to various response units.

It would be desirable to a wireless remote response system comprising a large number of remote response units with a single communication channel in a quick and reliable way actuate. also it is desirable to more skills provide or functions in a wireless remote response system. For example, would it is desirable to to allow a user such as a student an indication coming, whether a given answer is correct or incorrect. Except&lt;?page 3?&gt;the is it is desirable to in a remote response unit also providing a microphone to a user the ability to give the instructor to request an audio communication, the actual left control the audio channel in the hands of the instructor. It would be also desirable provide a interakti veres system that allows complex messages on an individual basis to students according to the correctness their answers will be issued. It would be desirable further, collect study answers that instead a multi-character length have by simply mark answers. It would further be desirable to effectively large blocks of text and other computer code from a central unit to the remote response units Downloading.

Accordingly it is an object of the present invention is a wireless remote response system indicate that a considerably improved flexibility and functionality over conventional Systems has.

the present invention provides a wireless remote response system Queries or collecting responses from multiple users on a Base unit before that from users in more remote response units are entered, each user is provided with a response unit is. The base unit transmits. on Base data packet over a wireless communication link to the plurality of remote response units, which decode the basic package and in a memory at each response unit loading a portion of the decoded base package. Each response unit examines the characters, which are loaded into memory, and determines each character in the portion of the decoded base packet of the particular response unit concerns. Each remote response unit then processes each character, belonging to that particular response unit. This may include, without restrictive to be the assembling and transmitting a response data packet over a wireless communication link from that particular response unit to the base unit. The response data packet contains any response that the of User is entered.

After another aspect of the invention, the part of the decoded Basic package, which is loaded into memory each remote response unit is meh rere characters, one each for a different response unit. The more characters confirmation mark lock in, to indicate that a valid Answer was previously received from the particular response unit. The more characters also contain a faultless character or characters correctly indicating whether a previously received response meets a correct answer in an answer key. The particular response unit can in different ways to the Correct characters respond. Only one display to the user proposed that a correct or incorrect response was received. Alternatively, the portion of the decoded base data packet, which everyone in the memory Remote response unit is loaded, contain more characters that global all response units or a group concern. In this way shows a particular response unit a first message to the is contained in the global characters in response to a predetermined Value of Correctly character that relates to that particular response unit, and displays a second message contained in the global characters is in response to a different value of character correctly, the this particular response unit relates.

After another aspect of the invention, the remote response units advantageously be divided into groups, and the part of the decoded base data Pact, which in the memory of each remote response unit Loading a determination of a group of response units contain relating to the individual characters. The decoded base data packet may further include a designation of which group of remote response units transmit a response data packet in response to the particular base data packet transmission should. In this way a group of response units can individually tailored messages in the same base data packet is received, prompting another group of response units, their response data packets transferred to. The part of the encoded base data packet, which everyone in the memory Remote response unit is loaded, also can contain multiple characters, the global all response units relate. These glo bal mark can in the memory at each response unit to any desired Purpose are stored, for example, as the operation code for the microcomputer, process any response unit. In this way, the Operation code and other data for the remote response units of the base unit be downloaded without a physical to require access to the remote response units to ROM devices or the like to exchange.

After another aspect of the invention, the base data packet a Determining a desired Answer length contained by the response units. Each response unit responds on this provision by assembling their response data packet, to provide the desired to include number of characters specified to provide the desired response length. In this manner, the response units are able to answers to against that consist of more than one character, while still the entire survey period is not longer than necessary retrieve all the answers or to collect. In addition to the build, a response data packet including each of the Be&lt;?page 4?&gt;users input response, the remote response unit a null data packet assemble, transmitting in response to a base data packet transmission is, even if a user has not entered a response. hereby may conduct an investigation of all response units, the base unit Ensure that all can response units respond, without the need for an answer must be entered.

After another aspect of the invention, the base data packets encoding and response data packets to a single technology and decoded. The values ​​of each bit are used as a time interval of at least one cycle of a periodic waveform encoding, where the time period either between successive rising edges or between successive falling edges of the periodic Waveform vari ated is. Thus, the time between rising Edges or between falling edges of successive Waveforms of a transferred will signal varied to any value for encoding of each bit. The decoding is performed, by measuring the time intervals between rising edges or between the falling edges of successive waveforms measured be. In a preferred form, it is determined whether each measured Time interval in one of at least two different, non-overlapping Periods falls, to determine a value of each bit. If a measured Time interval does not fall within one of the precise ranges, it is not it considered, and the entire data packet is ignored. In this way, the data transmission extraordinarily reliable, since each decoded bit is only accepted when its measured Precise time interval fits within a predetermined range. Since the data using a variable time interval are encoded varies the length of time the encoded packet as a function of the value of the respective Bits constituting the packet. To avoid the need to provide a sufficient time window available to the worst-case possibility To record, in which the bits that make up the package, the longest period coding have, the contents of each packet is checked prior to encoding to determine whether the encoded plurality of bits having the longest length would. If so, the bits are inverted, so that they, according to a shorter coded length be, and an indication of the inversion with the transmitted data packet delivered is a correct decoding at the receiving unit ensure.

The The method and system of the invention are defined in independent claims 1 and 23 defined. Some preferred features are specified in the dependent claims.

The The method may include determining whether each measured time interval in one of at least two distinct, non-overlapping time ranges falls, to decode a value of each bit.

A transfer is preferably ignored if at least one of the measured time intervals does not fall within one of the time ranges, Preferably, this characteristic is a number of characters making up the response data packet, wherein the data response packet length is controlled with said base data packet.

The contains base data packet preferably a determination of a characteristic of the base data packet. In this case, the characteristic of a base data packet its number of characters that make up the base data packet.

alternative contains the method provides a unique identification for each of the response units and determining each of the response units in a response interval, the said base data packet as a function of the characteristic of the Base data packet and the single identification of this responder follows, the remote response units are preferably divided into several groups, wherein the base data packet, a determination of a group of response units contains, the answer to the base data packet, the transmission of a response data packet closes preferably the transmission a null response data packet when an user does not answer has entered.

These and other items, Advantages and features of the invention will become apparent from the following Description with reference to the drawings.

<figref idrefs="S38">1</figref> is a block diagram of a wireless remote response system according to the invention;

<figref idrefs="S39">2</figref> is a block diagram of a system controller and a remote response unit;

<figref idrefs="S40">3</figref> provides a coding scheme according to the invention represents;

<figref>4</figref> provides a decoding scheme according to the invention represents;

<figref idrefs="S41">5</figref> provides the structure of a base data packet is;

<figref idrefs="S42">6</figref> provides the structure of a response data packet group;

<figref idrefs="S43">7</figref> is a flow chart the system controller;

&lt;?page 5?&gt;

<figref idrefs="S44">8th</figref> is a flow chart a remote response unit;

<figref idrefs="S45">9</figref> is a flow chart the transmission data function the system controller;

<figref idrefs="S46">10</figref> is a flow chart the receive data function of the system controller;

<figref idrefs="S47">11</figref> is a flow chart the transmission data function the remote control units;

<figref idrefs="S48">12</figref> is a flow chart the receive data function of the remote control units;

<figref idrefs="S49">13</figref> is a block diagram of a transceiver of the present invention in the is useful and

<figref idrefs="S50">14</figref> is a flow chart a method of efficiently transmitting large data blocks to the remote response units.

With Referring to the drawings and the illustrated embodiments contains a wireless remote response system <figref>20</figref> an instructor or base station base unit <figref>22</figref> and more remote response units <figref>24</figref> (<figref idrefs="S38">1</figref>). The base <figref>22</figref> contains a system control unit <figref>26</figref> antenna having a transmit and receive <figref>28</figref>. a wireless communication link with the transmission and receiving antennas <figref>30</figref> of each remote response unit <figref>24</figref> forms. The base unit <figref>22</figref> further includes a personal computer <figref>32</figref>. with an instructor over a wired connection channel as a serial channel <figref>34</figref>. Commands to the system controller <figref>26</figref> can deliver. The personal computer <figref>32</figref> may include operating software, which does not form part of the present invention in order of the Remote response units <figref>24</figref> received answers with an answer key Compare to count correct answers of each student and etc. perform statistical analysis. The base unit<figref>22</figref> can also over telephone lines or the like (not shown) with a central control area be connected in turn with a plurality of base units <figref>22</figref> in Connection can be. this makes possible it that the Instructor or teacher from a geographical distance can find the classroom or test chamber and at least about his Voice and data communication with the space in conjunction, in which each base unit <figref>2</figref> is arranged.

Each Remote response unit <figref>24</figref> includes an input device such as a keyboard <figref>36</figref>To receive user responses, and a display <figref>38</figref> to answers indicate that in the keyboard <figref>36</figref> be entered, as well as information from the base unit <figref>22</figref> transferred manner described below be. In the example shown, the remote response units have<figref>24</figref>, and the system controller <figref>26</figref> In substantially the same Hardware Architecture (<figref idrefs="S39">2</figref>). The system controller<figref>26</figref> contains a first microprocessor or microcomputer, the serial communication on the channel <figref>34</figref> of the computer <figref>32</figref> receives. Of the microcomputer <figref>40</figref> exchanges data signals over a bus <figref>39</figref> from extending to an RF transceiver <figref>42</figref> extends. A power management circuit <figref>44</figref> activated under the control the microcomputer <figref>40</figref> the transmission circuit of RF transceiver <figref>42</figref> about a line <figref>43</figref> only when it is time to a data packet transferred to.

A keyboard <figref>36</figref> and an LED or LCD display <figref>38</figref> put the respective input and output functions for the microcomputer is.

On contains the same manner the remote response unit <figref>24</figref> a microcomputer <figref>40 '</figref>, Of an input-output connection via a bus <figref>39 '</figref> With an RF transceiver <figref>42 '</figref> Has, the signals on an antenna <figref>30</figref> transmits and receives. On Power Management circuit <figref>44 '</figref> activated the transmission circuit of the RF transceivers <figref>42 '</figref> over a management <figref>43 '</figref> only if a transfer should occur. A keyboard<figref>36 '</figref> and a display <figref>38 '</figref> make the Input / Output Functions for the microcomputer <figref>40 '</figref> represent. Each unit <figref>24</figref> contains a microphone <figref>46</figref>, that with. an audio transmission device<figref>47a</figref> connected is, in turn, through an audio communication link defined by the antenna <figref>48a</figref>. <figref>48b</figref> is formed with an audio receiver <figref>47b</figref> in the system controller <figref>26</figref> connected is. This ermdglicht a voice communication by a user of the response unit with the instructor. If the instructor from the system controller<figref>26</figref> is, use the audio connection, a telephone line at <figref>49</figref> illustrated is. The audio communication link is connected to the system controller<figref>26</figref> and the response unit <figref>24</figref> by activating the transmission device <figref>47a</figref> and Recipient <figref>47b</figref> among the control of the microcomputer<figref>40</figref>. <figref>40 '</figref> only in response open to a command of the instructor.

In of the illustrated embodiment the microcomputer <figref>40</figref>. <figref>40 '</figref> are each an 8-bit microprocessor, the sold by Microchip Technology under Model No. PIC 17C42 will and a 2K byte internal ROM for storing control program has an internal 256 byte read-and-write memory and 128 bytes of external electrically erasable ROME. In a first preferred embodiment, the RF transceiver<figref>42</figref>. <figref>42 '</figref> Frequency-modulated, acoustic Oberflächenwellenresonatoreinrichtungen, the transfer at an intermediate band frequency of 418 MHz and can receive. includes the reception circuit a Bandpaßzwischenfrequenzstu fe and a phase locked loop&lt;?page 6?&gt;detector. Such a transceiver commercially Radiometrix Ltd., United Kingdom, under the model number BIM-418-F available.

In a second preferred embodiment operates the RF transceiver <figref>42</figref>. <figref>42 '</figref> at a frequency in the band 902-928 MHz (<figref idrefs="S49">13</figref>). The transceiver<figref>42</figref>. <figref>42 '</figref> contains a Receiving section consisting of an RF amplifier <figref>200</figref> and a mixer <figref>202</figref> is that of a 904.3 MHz signal a local oscillator <figref>210</figref> is provided to an average Frequency signal (IF) of 10.7 MHz dispense. The IF signal is of IF amplifier <figref>204</figref> strengthened and a detector and data splitter <figref>206</figref> supplied to the producing data signals to a microprocessor <figref>208</figref> are compatible. microprocessor <figref>208</figref> is through data lines <figref>39</figref>. <figref>39 '</figref> with each microcomputer <figref>40</figref>. <figref>40 '</figref> connected. The transceiver<figref>42</figref>. <figref>42 '</figref> also includes a transmission section, of a local oscillator <figref>210</figref> includes, of the by a data output microprocessor <figref>208</figref> and a current amplifier <figref>212</figref> modulates is, the output of the antenna <figref>28</figref>. <figref>30</figref> connected is. The local oscillator<figref>201</figref> is of a phase locked loop frequency synthesizer <figref>214</figref> stabilized, of a reference signal of 6.3 MHz from a frequency reference <figref>216</figref> contains. Of the current amplifier <figref>212</figref> becomes from a solid power switch <figref>220</figref> on- on and off of a solid state switch <figref>218</figref> among the control of power management circuits <figref>44</figref>. <figref>44 '</figref> by lines <figref>43</figref>. <figref>43 '</figref> is actuated. All circuit components, the transceiver to <figref>42</figref>. <figref>42 '</figref> form, are available from numerous commercial sources.

the keyboard <figref>36</figref>. <figref>36 '</figref> the embodiment illustrated is a commercially available 10 Finger membrane panel, the spectra of Symbol Company of Salt Lake City, Utah, is marketed. It is understood that the input device<figref>36</figref> not to a keyboard is limited, but it may also be a voice recognition device, a digitizer pad, an alphanumeric keypad, or some other Institutions act that can receive input from a user. In of the illustrated embodiment the display <figref>38</figref>. <figref>38 '</figref> a commercially available 24-character 2-line display. Such a display of Optrex Company of Japan under the model number DMC <figref>24227</figref> marketed. The FM communication link between the base unit <figref>22</figref> and the remote response units <figref>24</figref> is a half-duplex channel in which a base data packet <figref>50</figref> from the system controller <figref>26</figref> to all remote response units <figref>24</figref> transfer is, and the response data packets <figref>52</figref> be of any keyboard <figref>24</figref> individually within a time slot to the system controller <figref>26</figref> transfer, of each remote response unit is assigned. As from the following discussion closer can be seen to have the general data packet and the response data packet <figref>52</figref> the same fundamental Structure.

The Base data packet <figref>50</figref> and the response data packet <figref>52</figref> contain each a preamble <figref>54</figref>. <figref>54 '</figref>Consisting of nine Bytes of 55 hex is that the transmission as a data packet (<figref idrefs="S41">5</figref> and <figref idrefs="S42">6</figref>) Identified. The content the preamble is sufficiently precise to incorrect recognition of different EMI exclude sources. The preamble <figref>54</figref>. <figref>54 '</figref> followed by a sync byte <figref>56</figref>. <figref>56 '</figref>. which provides a time stamp for the receiving units can be coordinated in their response intervals. The remaining part of each data packet <figref>50</figref>. <figref>52</figref> consists of a header <figref>58</figref>. <figref>58 '</figref>, An MES SAGE <figref>60</figref>. <figref>60 '</figref> and a CHECKSUM <figref>62</figref>. <figref>62 '</figref>, HEADER<figref>58</figref> can a one-byte character field response <figref>59</figref> contain the identifying which of 5 groups of remote response units <figref>24</figref> on transmitted response data packet in response to this base data packet should. For size Groups of response units, for example, 250 units, it is appropriate that Units should be divided into groups, for example 50 units. This gives the system flexibility in the use of various Numbers of response units, in which the response intervals for phantom response units are eliminated. The response character field<figref>58 '</figref> contains a null character to the Data packet as a response data packet <figref>52</figref> to identify.

HEADER or packet header <figref>58</figref> in addition a Response Length <figref>72</figref> contain, the on the remote response units the number of characters informed to the MESSAGE field or message field <figref>60 '</figref> enclose. This allows the transfer of answers that longer than a single character under the control of the base unit. HEADER <figref>58</figref> in addition a basic package Langenfeld included to the remote response units of the number of characters in the base data packet <figref>50</figref> to instruct. This allows the transfer messages of different lengths globally to all response units in a Global Message field <figref>76</figref>, MESSAGE field <figref>60</figref> contains a group of characters <figref>64</figref>. <figref>66</figref>. <figref>68</figref> and <figref>70</figref>. the individual, the particular response units relate. the Data in the message field are structured so that each remote response unit is able to identify which character or characters which belong to this unit. However, the entire content of MESSAGE <figref>60</figref> from all receive remote response units and loaded into the memory. Each individual remote response unit checks the character memory location or storage locations, the particular one of the Unit is assigned, and responds to the value of the character at the particular memory location.

The MESSAGE field <figref>60</figref> contains a data structure of the verification Bytefeldes <figref>64</figref>. the each remote response unit indicating belongs to which each byte whether the previous data response packet of &lt;?page 7?&gt;transferred this unit was, to the system controller <figref>26</figref> validly received is. identified A field of correct / incorrect flag bits or flag bits each remote response unit whether the response contained in the previous response data packet was entered by the user, was correct or incorrect. The value the correct / incorrect flag bits is transmitted from the computer <figref>32</figref> fixed by comparing the received responses with a correctly answer key.

The MESSAGE field <figref>60</figref> contains Also Mike control bits <figref>68</figref>, Every Mike control bit <figref>68</figref> can of the instructor <figref>62</figref> about the computer <figref>32</figref> be fixed in response to a User audio communication with the instructor by entering a defined response in the keyboard <figref>36</figref> Calls. Each Mike control bit <figref>68</figref> is a particular remote response unit is assigned to a group of remote response units and when set from the microcomputer <figref>40 '</figref> processed. In response to a Mike actuated control bit the microcomputer <figref>40 '</figref> the Audio transmitter <figref>47</figref> For that particular remote response unit to a one-way audio communication of the remote unit user to the instructor via the audio receiver <figref>47b</figref> in of the. System controller<figref>26</figref> and a transmitter to the host site over a telephone line <figref>49</figref> to enable.

The MESSAGE field <figref>60</figref> contains also a Group Identity <figref>70</figref>. which can take a value 1 to 5 The Group Identity determines which group of remote response units <figref>24</figref> of the MES SAGE field <figref>60</figref> affected is. The values ​​of group identity Bytes<figref>70</figref> and Message field <figref>60</figref> can advantageously to a group other than the response byte <figref>59</figref> in the HEADER <figref>58</figref> are set. For example, the base data packet<figref>50</figref> the MESSAGE Group Identity <figref>70</figref> at the first group (group 1) and set the Response Byte <figref>58</figref> at a following group (group 2), whereby the group previously by transmission a response data packet answered, will be confirmed during a subsequent transmission can to the transceiver disable the remote response unit which previously transmitted a response data packet has the valid from the base unit was received.

The MESSAGE field <figref>60</figref> in addition a global MESSAGE field <figref>76</figref> contain, includes the character, the global all remote response units <figref>24</figref> or a group them concern. An application of the Global Message field<figref>76</figref> consists therein, the operation code for each microcomputer <figref>40 '</figref> down to load. This avoids the need for hardware modifications to the operational software of each remote response unit <figref>24</figref> hochzurüsten. Another application for Global Message field is in conjunction with the correct / incorrect flag bits <figref>66</figref>, Two or more messages in the Global Message field <figref>76</figref> be included, wherein the microcomputer <figref>40 '</figref> programmed are to one of the messages on the display <figref>38</figref> read if the correct / incorrect flag bit <figref>66</figref> a predetermined value has, and to read another message, if the flag bit a has another value. In this way the student can detail about incorrect Responses will be informed. In the illustrated embodiment has Global Message field <figref>76</figref> a capacity of 200 Character. Longer Code-chains at each microcomputer <figref>40</figref> through a series of transmissions be downloaded.

CHECKSUM <figref>62</figref>. <figref>62 '</figref> recruits Fehlererfassungsbyte at the end of each base data packet or response data packet ready. This byte is set to the value of the least significant Byte of the sum of all bytes in the respective packet of data set to to ensure that a valid Receipt of the package is caused, known as the skilled worker is.

The Response data packet <figref>52</figref> contains the response message or Keystroke characters in the message field <figref>60 '</figref>, In one embodiment, the response the Message field <figref>60 '</figref> on single character, which produces a single keystroke, the with the keyboard <figref>36</figref> is inputted. Alternatively, the response in the Message field <figref>60</figref> have a multi-character length, the number the mark by the Response Length <figref>72</figref> fixed is or determined. In this way, the system controller<figref>26</figref> the length of the Response from the response data packet <figref>52</figref> control. The microcomputer<figref>40 '</figref> each remote response unit <figref>24</figref> responds to the value in the Response Length <figref>72</figref> set is, by assembling the response data packet <figref>52</figref> with the desired number of characters through the Response Length <figref>72</figref> been showing becomes. In this way, Responses from multi-character words made by the remote response system <figref>20</figref> to be collected.

In configured a further alternative embodiment the microcomputer <figref>40</figref> the response data packet <figref>52</figref> including a Zero input in the Message field <figref>60 '</figref>If the user is not using the keyboard <figref>36</figref> a has entered answer. If such a null response data packet is used, transmits each response unit <figref>24</figref> a response data packet in response to each base data packet that was transmitted from the base unit, regardless of whether a user has entered a response or not. To this Example, a base unit an examination of each remote unit perform to to determine if the remote unit within a non-interfering communication range the base unit is.

&lt;?page 8?&gt;

Each Remote response unit <figref>24</figref> is a unique identification number or address. assigned. Each remote response unit is also a be assigned to the plurality of groups, which in the example shown, as groups <figref>1</figref> to <figref>5</figref> are designated. The identification number or group number is added to a response unit memory. Upon receiving and decoding a base data packet <figref>50</figref> certainly each remote response unit by calculating the time interval following Sync byte or synchronization byte <figref>56</figref>When answered shall be. This calculation is based on the position that the Identification number for these remote response unit takes in, their group, and on the Value; Basisdatenpaketlängenbyte<figref>74</figref> and the Response Length <figref>72</figref>, If no Basisdatenpaketlängenbyte or Response Length is used, a default value is used.

As mentioned above, are the base data packet <figref>50</figref> and the response data packet <figref>52</figref> at the respective system controller <figref>26</figref> and the remote response unit <figref>24</figref> assembles and to the RF transceiver <figref>42</figref>. <figref>42</figref> frequency-modulated. The received FM transmission is used by the RF transceiver <figref>42</figref>. <figref>42 '</figref> the lowing are received, unit received, frequency is reduced and recorded. The detected signal has an analog waveform with peaks and valleys, which substantially coincides with the transmitted Data packet match. The analog signal generated by the detector, is of a data slicer (not shown) processed, comprising a Waveform causes, the better defined rising and falling points and has an amplitude that for the processing by the microprocessor <figref>40</figref>. <figref>40</figref> suitable is. Of the. microprocessor<figref>40</figref>. <figref>40 '</figref> performs the final step in the decoding process through, by responding to the rising Edges of the data stream from the RF transceiver <figref>42</figref>. <figref>42 '</figref>To the 0-value bits and to identify the 1-value bits in a manner which is now described becomes.

Each Bit of base data packet and the response data packet is as follows encoded and decoded. A 0-bit<figref>80</figref> consists of a whole Cycle of a square or rectangular wave, measured from a rising edge <figref>82</figref> to the subsequent rising flank <figref>82</figref> (<figref idrefs="S40">3</figref>). Alternatively, the Waveform cycle are measured from the falling edge <figref>84</figref> to, the next falling edge (not shown). The advantage of this coding technique is that the Interval between rising edges, or alternatively between falling edges of a transferred Data pulse is exceptionally constant whereas the interval between a rising edge <figref>82</figref> and a subsequent falling flank <figref>84</figref> is ziernlich inconsistent and environmental effects subject as a signal strength and temperature. The length L0 of the 0 bit is at a predetermined time interval by the microprocessor <figref>40</figref>. <figref>40 '</figref> encodes the output with a a certain repetition rate toggles, to generate the 0 bits. A 1-bit<figref>86</figref> will of his leading edge <figref>88</figref> up to the leading edge <figref>88</figref> the subsequent waveform defined. The waveform cycle has a L1 time interval that is much less than the interval L0 for the 0-bit <figref>80</figref>, This is accomplished by generating the 1 bit by the microprocessor <figref>40</figref>. <figref>40 '</figref>That his Outputs back with his vorbestimm th frequency and forth, the higher than that used to generate the 0-bit <figref>80</figref> used becomes. It is understood that the above description is to the effect desired, whether the 0-bit or 1-bit with a longer Waveform is encoded, wherein the 1-bit with a length L0 and a 0 bit. with a length can be coded L1. It is also in the context of the invention, that a bit more complete waveforms of square or rectangular shaft could be encoded. The duration of an interval L0, L1 starts and ends, however the leading edges or alternatively the trailing edges of each waveform, In the illustrated example, L0 is 185 microseconds and L1 is 90 microseconds.

There encoding the data using a variable time interval are varied, the encoded packet in the time period as a function the value of the respective bits <figref>81</figref>That the package (<figref idrefs="S40">3</figref>) form. In order to avoid that one, sufficiently large Timeframe for the worst case possibility made available must become, the data <figref>81</figref> before encoding is checked to determine whether the Majority of bits encoded in this case, 0 corresponding to the largest length would. In the illustration of <figref idrefs="S40">3</figref> would the required period to transfer the data <figref>81</figref> exceedingly long when the 0-bit encoded with the greatest length would. As a result, the data is <figref>81</figref> to <figref>81 '</figref> converted, thereby mainly consist of one-bits encoded with a shorter time length be. In this way, that is for transmission of the data<figref>81</figref> required length interval never longer, than would be required, a to transmit data word, consisting of 50% of its bits encoded according to the longest duration are.

A Bit decoding technique <figref>90</figref> is in <figref>4</figref> shown. Microcomputer <figref>40</figref>. <figref>40 '</figref> contains an internal counter which the intervals between the rising edges of the bit-sliced Data stream D counts, the of the RF transceiver <figref>42</figref>. <figref>42</figref> comes. The length of Interval, which is defined by the microcomputer counts is then with two separate, non-overlapping areas compared. A number must in one of the areas covered in order to be decoded as a valid bit: A bit number <figref>92</figref> is below the limit of the interval, and a bit number of <figref>94</figref> thereof is larger than the limit Range, Thus would numbers <figref>92</figref> and <figref>94</figref> as invalid and &lt;?page 9?&gt;inadmissible considered if they do not fall within the other non-overlapping area, wherein the number would be decoded as bit opposite in this case. A number <figref>96</figref>Which falls within one of the areas is decoded as a Bit, which is defined by this field. Since a number of bits to be greater must as the minimum of a range and less than the maximum of a range, order valid as a or permissible Bit to be decoded, and the ranges do not overlap, is the ability erroneous Decoding a bit small. Each bit that is decoded erroneously is, would probably eliminated by the CHECKSUM calculation based on the CHECKSUM byte <figref>62</figref> is performed. If the receiving Module one of the bits can not decode or if the CHECKSUM calculation invalid is, the entire received data packet is left aside and the receiving unit not indicate that data packet. The nature of the remote response system <figref>20</figref> However, is such that after putting aside a transfer the receiving unit fully is able to respond to a subsequent data packet. If regarding a remote response unit. The base unit in a manner be positioned such that a Communication between the two units is unsuccessful again has the remote response unit in terms of the base unit to be repositioned in order to be useful. According to the present Invention, the remote response unit can be programmed to a response data packet with a 0 MESSAGE <figref>60 '</figref> transferred to, when a user has not entered a response, the base unit the instructor about inform that the particular Remote response unit except Operating or otherwise inactive is.

the System controller <figref>26</figref> includes a control program <figref>100</figref> (<figref idrefs="S43">7</figref>). The control program <figref>100</figref> is at <figref>102</figref> initialized by ramping up the controller <figref>26</figref>, A routine<figref>104</figref> checked whether the personal computer <figref>32</figref> at <figref>106</figref> formulated tasks has and responds to each object formulated. The program<figref>100</figref> transfers in <figref>108</figref> on Base data packet <figref>150</figref> to all remote response units <figref>24</figref>, The program then provides a time delay <figref>110</figref> the final period, so that the remote response units <figref>24</figref> form their answers can. At the beginning of an interval <figref>1</figref> at <figref>112</figref> receives the System controller <figref>26</figref> a response data packet from the first keyboard that is intended to answer, decodes the response data packet and passes the decoded data to the base personal computer <figref>32</figref> at <figref>114</figref>, The program then proceeds to the next interval at <figref>116</figref> on and receives, decodes and forwards the response data packet from the next keypad at <figref>118</figref> to the personal computer <figref>32</figref> continue. After this been checked all intervals are, control returns to the routine <figref>104</figref> Back to determine, whether a new task or question from the computer <figref>32</figref> requested becomes. The software in the computer<figref>32</figref> the instructor can a task for the system controller <figref>26</figref> formulate repeated to transmit basic data packets, until valid or permitted Responses are received from all remote response units, or for a certain number of cycles or a certain time length. Thereby , the routine executed by the steps of <figref>108</figref> to <figref>118</figref> is defined, are repeatedly carried out under the instructions.

On control program <figref>120</figref> is repeated at each remote response unit accomplished (<figref idrefs="S44">8th</figref>). The program is in<figref>122</figref> by raising the unit initializes and waits for <figref>124</figref> to receiving a base data packet from system controller <figref>26</figref>, If the base data packet is received, the remote response unit examines the Characters in the HEADER field <figref>58</figref>To determine whether that particular Remote response unit in the group is represented by the Gruppendesignator <figref>59</figref> to the Reply is determined at <figref>126</figref>, The particular remote response unit also checks the MESSAGE field <figref>60</figref> and verified by the Group Identity <figref>70</figref>. whether the content of the message field the group is concerned, the Member is that particular response unit. Each response unit within the of the Group Identity <figref>70</figref> certain group reviews the Acknowledge Bit <figref>64</figref>. the correct / incorrect FLAG bit <figref>66</figref> and Mike control bit <figref>68</figref>. which is part of the specific unit within the group and answers on the values ​​for these specific bits are set. If the Acknowledge Bit<figref>64</figref> for this particular unit is set, the system controller <figref>26</figref> allowed the received previous response data packet from the particular response unit is sent. If the correct / incorrect flag bit or flag bit<figref>66</figref> on is properly set, the microprocessor <figref>40 '</figref> a "Correct Indicator" or "incorrectness Indicator" (not shown) come on or a specific indication on the display <figref>38</figref> provide. In a preferred embodiment can be done that only the uppermost horizontal one correctly display characterized Segment of a seven segment display of the display <figref>38</figref> lights, and the incorrectness indicator could the bottom horizontal segment of the display <figref>38</figref> to shine blank or vice versa. Alternatively, the microcomputer<figref>40 '</figref> to a value the correct / incorrect Rag bit respond by indicating a portion a Global Message field <figref>76</figref>Arriving at the correct Answer heard or any other part of the Global Message field <figref>76</figref>Which came to a incorrect response belongs. If Mike Control Bit <figref>68</figref> for the particular remote response unit is set, the microcomputer responds <figref>40 '</figref> by operating the audio transmitter <figref>47a</figref>. a one-way audio communication between the microphone <figref>46 '</figref> the user and to allow the instructor. The remote response unit <figref>24</figref> responds also to the Response Length <figref>72</figref> and the Base data packet length byte <figref>74</figref>. appro around the&lt;?page 10?&gt;designated interval timing set as described above is. When the installation task<figref>126</figref> is completed, makes a Interval timer at <figref>128</figref> and the control waits at <figref>130</figref> on the appropriate interval for this particular response unit for transmission. A response data packet is at <figref>132</figref> while transmit the appropriate interval.

the Routine for this system controller <figref>26</figref> for setting and transmitting a base data packet <figref>108</figref> is also in <figref idrefs="S45">9</figref> shown. The control program <figref>100</figref> initiates a transmission by system controller <figref>26</figref> by taking any Task of the personal computer <figref>32</figref> at <figref>104</figref> required becomes. The transmission part the RF transceiver <figref>42</figref> is at <figref>134</figref> operated. the preamble <figref>54</figref> becomes at <figref>136</figref> to all remote response units <figref>24</figref>, transfer, to the data received from the RF transceiver <figref>42</figref>, RF transceiver <figref>42</figref> as transmitted each remote response unit are to stabilize. The data can be stabilized because the sensing portion of the RF transceiver is a finite stabilizing Time interval has. The sync byte<figref>56</figref>, HEADER package <figref>58</figref>. MESSAGE package <figref>58</figref> and CHECKSUM <figref>62</figref> become at <figref>138</figref> transfer. The transfer is then at <figref>140</figref> turned off, and an interval timer is at <figref>142</figref> started. The interval timer brings the response data packets of the remote response units <figref>24</figref> with any particular response unit in line, decodes the packets and makes the information available for the personal computer <figref>32</figref> available.

the System controller <figref>26</figref> receives keyboard data under control the program <figref>100</figref> by repeated transmission of the basic package and monitoring subsequent intervals the response data packets from the response units (<figref>108</figref>. <figref>110</figref>. <figref>112</figref>. <figref>116</figref>) (<figref idrefs="S46">10</figref>). The receiving response data packets and decodes the data to the computer <figref>32</figref> (<figref>114</figref>. <figref>118</figref>) passed. After the entire group of remote response units<figref>24</figref> transmitted response data packets , has compiled the system controller <figref>26</figref> the Acknowledge Bit <figref>64</figref> at <figref>144</figref> With a validity test, received from each response data packet is made.

Around to transmit the response data packets, each containing Remote response unit <figref>24</figref> a base data packet from the system controller, at <figref>124</figref>, about the RF link between the antenna <figref>28</figref> and antenna <figref>30</figref> (<figref idrefs="S47">11</figref>). Microcomputer <figref>40 '</figref> decoded the received data and determines at <figref>126</figref>Whether this Remote response unit in the group is that by Response <figref>59</figref> certainly is to transmit a response, and in the group through the Group Identity <figref>70</figref> as belonging to the message field <figref>60</figref> identified is. If so, the characters in the are. MESSAGE<figref>60</figref>. belonging to the particular remote response unit, wherein <figref>126</figref> withdrawn. When the remote response unit in the group is that by Response <figref>59</figref> to transfer a response is determined to start the microcomputer <figref>40 '</figref> an interval timer and waits for the interval in <figref>126</figref> is determined from, associated with the particular response unit to the answer. If the interval arrives, the microcomputer switches <figref>40 '</figref> the RF transceiver <figref>42 '</figref> at <figref>148</figref> on, to the transmission part to stabilize, and transmits the preamble <figref>54 '</figref>To the data in the transceiver <figref>42</figref> the system controller <figref>26</figref> at <figref>150</figref> to stabilize. The remote response unit <figref>24</figref> then transmits the sync byte <figref>56 '</figref>, HEADER <figref>58 '</figref>MESSAGE characters <figref>60 '</figref> and CHECKSUM <figref>62 '</figref> to the system controller.

Each Remote response unit <figref>24</figref> receives the data packet from the System controller via the RF link at <figref>126</figref> (<figref idrefs="S48">12</figref>). If all bits without rejection are decoded, CHECKSUM is for the entire base data packet at <figref>164</figref> verified to the transmission to accept or reject, The timer confirmation and mode information is at <figref>126</figref> removed when the response unit in the group is that of the Group Identity <figref>70</figref> designated is. It is then at<figref>166</figref> determines whether the acknowledge bit set is that at the particular remote response unit in the Acknowledge Bit <figref>64</figref> belongs. If This being so, the transceiver <figref>42 '</figref>, for this keyboard at<figref>168</figref> off. If at <figref>166</figref> it is determined that the acknowledge bit for that particular Remote response unit is not set and the remote response unit is in the group by Response <figref>59</figref> to transfer a response is determined to start the microcomputer <figref>40 '</figref> the interval timer at <figref>128</figref> and waits for the calculated transmission interval at <figref>130</figref>, The remote response unit<figref>24</figref> transmits the response data packet at <figref>132</figref>, When the remote response unit is not in the group is that by Response <figref>59</figref> is designed to transmit a response, expects the microcomputer <figref>44 '</figref> his response byte <figref>59</figref> and then transfers a response data packet.

On process <figref>170</figref> for transferring a great Data block to all remote response units to time-effective manner is in <figref idrefs="S50">14</figref> shown. The method<figref>170</figref> becomes initiated by the personal computer connected to the system controller <figref>26</figref> connected is and the great Divided data block, so that in a multiple-packet data stream at <figref>172</figref> transfer becomes. The multiple-packet data stream is at<figref>174</figref> to the System controller <figref>26</figref> and passed in its entirety to all remote units in <figref>176</figref> transfer. Each remote response unit<figref>24</figref> decoded the multi-packet data stream and determines whether each packet exactly was received. A bit pattern or bit map in each remote response unit<figref>24</figref> out the bits formed, indicating which packets were received exactly. The system controller <figref>26</figref> transfers in <figref>178</figref> a central Datenpa&lt;?page 11?&gt;ket <figref>50</figref> to all remote response units <figref>24</figref> the according to the requirement of the bitmap Reports from all remote response units is formatted. A bitmap is at Master<figref>180</figref> in the system controller <figref>26</figref> from the Response data packets <figref>52</figref> formulated with bitmaps the various remote response units are coded. The system controller checks the Master Bitmap at <figref>182</figref> and sends all the packets according to the packets, which were not even received from a remote response unit exactly how reproduced in the master bitmap. The bitmaps of each remote response units become at <figref>184</figref> collected to the additional exactly received data packets reproduce in the same way as before. The master bitmap at <figref>186</figref> brought up to date and there is at <figref>188</figref> certainly, whether the number of repetitions, the strength to obtain a 100% accurate Packet data transmission is set, is reached, if not, is another cycle <figref>182</figref>. <figref>184</figref>. <figref>186</figref> of Sending missing packets repeatedly, the bitmaps are integrated at each Fernantwortein brought up to date, and the master bitmap is on the brought new status. If a 100% accurate transmission is reached or the retry limit at <figref>188</figref> is reached, a Message to the base personal computer at <figref>190</figref> sent. The instructor may require that additional repetitions are attempts or he may give verbal instructions to the user when one or more remote response units do not complete the multiple-packet data have received exactly, to move to another location, to the process for to repeat.

Of the Advantage of the process <figref>170</figref> is that the period of time, the for energizing the transceiver <figref>42</figref> all remote response units <figref>24</figref> required is, after all data packets transmitted are, is avoided. This time interval can be significant, since it is multiplied by each keyboard. By dividing the very extensive transfer the data into multiple data packets, only the data packets that not exactly by all units. received repeated. This avoids the need for the entire very long data transfer to repeat, if one or more remote response units entire transmission have not received exactly.

Thus the present invention provides a wireless remote response system before, which has an excellent noise immunity and a tolerance for variations in the timing of the transmitted Signals, while a virtually error-free operation is ensured. The system has excellent flexibility, transferring the of message data from the base unit to the remote response units allows the same base data packet, the transmission the response data packets synchronized from the remote response units. Different groups of response units, which are divided into groups are to a large record number of response units on a single RF link, can advantageously be determined by a base data packet to: <ul><li>(A) transmitting a response data packet and</li><li>(B) processing the message data.</li></ul>

the Message data take the confirmation bit for validly received Answers to to the public to induce response units to stop the transfer. correctness mark and characters for insertion of a microphone can transmit in addition to the message data be and are processed by the remote response units. Also allows the Invention downloading a large array of characters globally to all remote response units, namely an efficient manner. This allows it z. B. the user great feedback messages display, in response to a correct or incorrect answer and the downloading of the operation code for each remote response units and the downloading of code for other purposes. In addition, the ability the base unit for instructing the remote response units on the length of intended responses from each of the remote response units and the ability the remote response units. to respond to such a provision, by a suitable response data packet is structured, collecting of responses that are more complex than a single character.

changes and modifications of the embodiments described within the scope of Principles of the invention, which is limited only by the scope of the appended claims.