CMX881 Baseband Processor for PMR and Trunked Radios D/881/17 April 2009 Full-Feature Audio-Processing, Signalling and Data for Half Duplex Dual-Mode Analogue PMR and Trunked Radios Features Automatic signal type scanning and IRQ on Voice processing facilities, including Tx and Rx detection of valid Rx signals, level or RSSI gain setting and voice/subaudio filtering Tone generator for caller recognition tunes C-BUS serial host interface Programmable powerdown control RF interface allowing 1 or 2 point modulation Programmable signal detection thresholds Programmable soft limiter Low Power operation with Zero Power mode Programmable Selcall Codec Zero Talkdown CTCSS decoder performance Uncommitted Aux ADC with switchable input prevents dropouts to monitor signals DTMF transmitter Meets ETS 300 086, MPT1327, PAA1382 and Standard (39-tone) CTCSS and 23/24 bit DCS ETS 300 230 specifications Codecs Robust half-duplex FFSK/MSK modem, 1200/2400bps with CRC and parity generator/checker, gets data through when signal is too degraded for voice for text messaging/paging, location transfer, etc. applications. 1.1 Brief Description CMX881, a full-function half-duplex audio and signalling processor IC for both PMR and Trunked radio systems suitable for complex and simple end-designs. Under the control of the host C, all voiceband requirements are catered for: voiceband and sub-audio filtering, pre/de-emphasis and audio routing and global level setting with single or two-point modulation in the transmit path. The combination of CTCSS and DCS functions and Selcall operation of this product offer, under software control, increased functionality, versatility and privacy. To cater for call setup and system signalling the CMX881 provides an embedded 1200/2400 bps MSK/FFSK free-format modem for text messaging/paging, passing GPS location data with checksum generation and reception and sync detection in the Rx path. 2009 CML Microsystems Plc PMR Baseband Processor CMX881 With ultra low power requirements and graduated powersave, this product requires a smaller, lower- power C than existing PMR or trunked radio solutions. It is available in compact SSOP and TSSOP packages. 2009 CML Microsystems Plc 2 D/881/17