CMX869 V.32bis Modem

The CMX869, a V.32bis modem IC, is targeted at communications terminals which do not need V.90 data rates or have low-power requirements which preclude high-speed operation. The maximum speed of 14.4kb/s will meet the requirements of many mid-range applications, while the low operating and very low standby currents are attractive for battery powered terminals. The ring/line reversal detection circuit which is operational in the standby mode further conserves power by allowing the host microcontroller to switch to a low power mode when not in use. A relay drive output is available, which, once again, reduces host I/O requirements.
The interface to the host controller is a C-BUS serial link running at 150kb/s. All data transfers pass through this link including access to the modem control and status registers.
V.42 is supported by the provision of HDLC (programming option) to generate frames and CRCs, and to detect transmission errors.
The CMX869 can transmit and detect standard DTMF and modem calling/answering signals or user-programmed single or dual tone signals. A general purpose Call Progress signal detector is also included. Flexible line-driver and receive hybrid circuits are integrated on-chip, requiring only passive external components to build a 2- or 4-wire line interface.

For further information please contact kellyb@spectre-online.co.uk