For the use of Radio and TV telephone talk shows, or communicational sound systems for various institutions.

The device is a 9,5" designed module. On demand it's possible to have it built as a rack system as well. The product was mainly developed for TV or radio talks shows where the device forms the two lined-duplex transfer unit into a four line one. This means, that for the sake of easier mixing and signal procession the device separates the incoming (telephone) signal and the own voice, so these can be amplified and controlled separately.

Under own voice in this case we mean the microphone sound which is created by the microphone used by the interviewer or guests in the studio. The own voice's microphone signal has to be amplified. The amplified signal goes straight to the MIC.IN input (this can come from the mixing desk's microphone channel's DIRECT-OUT). By converting from four to duplex the own voice appears on the phone line, so the phone user will hear it.

The phone user's sound level can be set with the TEL.TO SEND adjuster. This signal appears on the device's OUTPUT connectors. From this output it can be sent to the mixers. The LINE BALANCE adjuster provides the best separation between the phone user and own voice. This function has to be used when booting for the out-tuning of the connected phone lines. With the use of the TONE GEN switch the inner sound generator gives the signal on the phone line.

With the setting of the LOW and HIGH adjusters on the OUTPUT connector (incoming sound) the appearing generator-sound has to be tuned to minimum. After the setting has been done the generator should be turned off. The phone line's presence is shown by the LINE led. In the case of an incoming call the "picking up" the phone happens with the TEPHONE ON switch. This function can be also operated from the distance, with the use of the connected switch to the TEL.ON REMOTE's stand located on the back of the device TC124 technical datas (PDF)