M3541

The M3541 is a keypad switchable LD/DTMF dialer devices designed for use in low cost, dual dialing mode telephoneinstruments. It is suitable for sending telephone numberswithout limit and an on-chip memory allows numbers of up 31 digits to be retained for redialling later. The low power CMOS design allows the number in the memory to be maintained indefinitely (until overwritten) by a minimal current leaked from the telephoneline. A particular feature of this device is the facility for the user to switch dialling mode fromLD to DTMF via the keypad during the course of a call. This is intended for uses such as home banking, access to long distancetrunk service, credit cardverificatios andother applications which require data to be sent at low speed once a connection has been established.