Fixed cellular terminal for two-wire telecommunications services

摘要

To access a mobile communications network and provide basic telecommunications services of the public switching network for an ordinary telephone terminal (TT2) connected to it. This terminal is derived from a GSM mobile cellular terminal, employing four-wire transmission over the whole path, including a two-wire conversion circuit (H) connected between the transmitting (TP) and receiving (RP) pairs and the subscriber line (SL) of the telephone terminal (TT2). It also includes an echo canceller (EC) situated before the two-wire conversion circuit (H), in order to subtract part of a first signal (FS) directed towards the telephone terminal (TT2) from a second signal (SS) coming from the latter and in this way compensate part of the echo produced mainly by the telephone terminal (TT2) and by the two-wire conversion circuit (H).