PBL38570

No input should be set on higher level than pin 4 (+C).

PBL 38570 is a monolithic integrated speech transmission circuit for use in electronic telephones. PBL38570 is designed to accomodate either a low impedance dynamic or an electret microphone. A separate input for DTMF dialling tones that is controlled by a mute signal, and a signal summing point at the transmitter input, are available.

An internally preset line length compensation ofPBL38570 can be adjusted with external resistors to fit into different current feed systems as for ex. 48 V, 2 x 200 ohms, 48 V, 2 x 400 ohms and 48 V, 2 x 800 ohms. The line length compensation PBL38570 can be shut off in either high or low gain mode. Application dependent parameters such as line balance, side tone level, transmitter and receiver gains and frequency responces are set independently by external components which means an easy adaption to various market needs.

The setting of the parameters of PBL38570 if carried out in certain order will counteract the interaction between the settings.

A number of different DC - supplies are provided to feed microphones and diallers.