Method and apparatus for telephone/facsimile switching

p0001The invention relates to a method for telephone fax switching of the kind specified in the preamble of patent claim 1 in more detail and to an apparatus for telephone-fax switching, as defined in the preamble of claim 2. Such methods and devices are described in various embodiments in the literature and commercially available.

p0002To support and the simultaneous operation of multiple services, voice transmission on the one hand and the fax service on the other hand, many devices are known that allow the selective operation of fax and telephone terminal equipment with limitations on a telecommunications connection. These devices are either included in a combined fax / telephone terminals, designed as a separate control gear or integrated into small telecommunications equipment and are relatively expensive and are always subject to ongoing external power supply, of ballasts usually means power adapter.

p0003In analog devices area several telephone terminal equipment, telecommunication systems are often operated with or without additional functions and answering machine to a subscriber line that often also require a permanent power supply and work together with a fax machine on an analog select terminal from handling her even side by side should. Often caused mutual interference, particularly of a fax machine and answering machine, and a plurality steady stream consumers cause considerable costs.

p0004The invention has for its object to reduce these costs and provide a phone-fax switching opportunity for a connection on the analog network terminator transfer point without additional external power supply, with no changes in the existing telekommunaktiven periphery and without the need for adjustments or programming.

p0005The invention solves this problem with the steps set out in the characterizing part of claim 1.

p0006A suitable device for the solution of this problem is described in the characterizing portion of claim 2.

p0007The invention and its operation will be described below with reference to Ausführtrngsbeispielen detail. In the accompanying drawings show:<dl id="dl0001" compact="compact"><dt>Fig. 1</dt><dd>a schematic representation of the attachment,</dd><dt>FIG. 2</dt><dd>the associated electrical wiring of the NT can and</dd><dt>Fig. 3</dt><dd>a Blockschltbild to explain the method and apparatus.</dd></dl>

p0008The attachment shown in FIG. 1, the insertion of a telephone-fax-switch between the TFU analog network terminal NT and provided for connecting a fax machine EE.sub.2 junction box TAE shown. Another terminal EE 1 is for other telephone terminal equipment, eg telephone, with additional functions or a small telecommunications system, including a telephone answering machine, provided.

p0009The connection of the fax terminal is carried out directly on the phone-fax-switch TFU. The energy required to run the Phone fax switch TFU is from the ringing, if necessary, via current transformers, and / or the supply voltage of the switching center to La / Lb, having regard for higher currents by a charging capacitor obtained.

p0010The circuit diagram shown in FIG. 2 shows the internal electrical wiring of the power junction box NT with the connection to the phone-fax-switch TFU via a four-wire power cord.

p0011The block diagram shown in FIG. 3 is used for explanation of the method and of the apparatus and represents only one of many possible implementation variants.

p0012For incoming calls, both terminals are called EE1 and EE2 with the first Rufwechsel, wherein the caller identification 1 with the connected relay K3 the terminal EE2, which is turned over the TFU, switches off after about 100ms. The terminal EE2 but transferred after the first call in a receivable state and is still supplied via the contacts K1 and K5 with ringing voltage. In response, the loop current recognition phone 2 of this call will be turned off. The energy (voltage Vcc), which requires the phone-fax-switch TFU for further temporary handling (switching routines) is out of the loop voltage La - Lb won.

p0013If a connection is made through the terminal EE1, ie detected loop current phone, the CNG (Connector for Line / trunk group) detection 3 active.

p0014In the case of CNG detecting 3, the reset circuit 4 is active for resetting and switching, ie the terminal EE2 is switched active, K3 relay is reset and the terminal EE1 is deactivated (K2 Ralais is set).

p0015If the fax communication ends, ie, it is detected by the loop current recognition fax 5 no loop current, the K2 relay resets. The initial state is restored.

p0016The main advantages of the invention are:<ul><li>The phone-fax-switch TFU finds its Anschaltemöglichkeiten the analog network terminator handover point.</li><li>An existing telekommunaktiven periphery no changes need to be made.</li><li>There are no settings or programming on the phone-fax-switch TFU make.</li><li>It requires no additional external power supply.</li></ul>

p0017Functional sequence of phone-fax switching:<ul><li>1. Incoming call delayed response K3 relay after about 100 ms. K3 relay set, fax is turned off.</li><li>2. Sign Tel + AB Loop current available Evaluation CNG active</li><li>3. In CNG: K3 relay reset, set K2 relay</li><li>4. Fax Operation</li><li>5. Fax Operation end, Is = 0 Reset K2 relay,</li><li>. 6 <u>No CNG</u>, No fax operation no reset K3 relay, no set K2 relay,</li><li>7. End AB or Tel-operation, Reset K3 relay without setting K2 relay.</li></ul>