DESCRIPTION
The DS2167 and DS2168 are dedicated digital signal processor (DSP) CMOS chips optimized for Adaptive Differential Pulse Code Modulation (ADPCM) based compression algorithms. The devices halve the transmission bandwidth of “toll quality” voice from 64K to 32K bits/second and are utilized in PCM-based telephony networks.

FEATURES
• Speech compression chip compatible with standard ADPCM algorithms:
    – DS2167 supports “new” T1Y1 recommendations (July 1986) and “new” CCITT G.721 recommendations
    – DS2168 supports “old” CCITT G.721 recommendations
• Dual independent channel architecture – device may be programmed to perform full duplex, 2-channel expansions, or 2-channel compressions
• Interconnects directly with µ-law or A-law codec/filter devices
• Serial PCM and control port interfaces minimize “glue logic” in multiple channel applications
    – On-chip channel counters identify input and output timeslots in TDM-based systems
    – Unique addressing scheme simplifies device control; 3-wire port shared among 64 devices
    – Bypass and idle features allow dynamic allocation of channel bandwidth, minimize system power requirements
• Hardware mode intended for stand-alone use
    – No host processor required
    – Ideal for voice mail applications
• 28-pin surface-mount package available, designated DS2167Q/DS2168Q