The AS253x is a very flexible CMOS integrated circuit family that contains all the functions needed to build a high performance electronic telephone set with basic features.
The AS253x incorporates a line interface, a speech circuit, a dialler and ringer. It is a real single-chip / single-die IC with 28 pins. It allows either package mounting or chip-onboard mounting.
The device is available in 4 versions (pin-compatible) with different features ranging from LNR only (last number redial) to 4 direct (one-touch) memories and 10 indirect (two-touch) memories. The sliding cursor procedure makes the LNR function easy to use under various PABX systems.
The versatility of the circuit is provided by pin options and a few external components. This allows fast time-to-market and easy adaptation to different PTT requirements. A unique EMI performance has been achieved due to the consequent use of CMOS amplifiers.
The AS2534BT is a Multi-Standard CMOS Telephone IC for Basic Telephones with LNR only no direct/indirect memories, available in a 28-pin plastic SOIC package.