MT9126

• Full duplex transcoder with four encode channels and four decode channels
• 32 kb/s, 24 kb/s and 16 kb/s ADPCM coding complying with ITU-T (previously CCITT) G.726 (without 40 kb/s), and ANSI T1.303-1989
• Low power operation, 25 mW typical
• Asynchronous 4.096 MHz master clock operation
• SSI and ST-BUS interface options
• Transparent PCM bypass
• Transparent ADPCM bypass
• Linear PCM code
• No microprocessor control required
• Simple interface to Codec devices
• Pin selectable m-Law or A-Law operation
• Pin selectable ITU-T or signed magnitude PCM coding
• Single 5 volt power supply

The Quad ADPCM Transcoder v is a low power, CMOS device capable of four encode and four decode functions per frame. Four 64 kbit/s PCM octets are compressed into four 32, 24 or 16 kbit/s ADPCM words, and four 32, 24 or 16 kbit/s ADPCM words are expanded into four 64 kbit/s PCM octets. The 32, 24 and 16 kbit/s ADPCM of MT9126 transcoding algorithms utilized conform to ITU-T Recommendation G.726 (excluding 40 kbit/s), and ANSI T1.303 - 1989. Switching, on-the-fly, between 32 kbit/s and 24 kbit/s ADPCM, is possible by controlling the appropriate mode select (MS1 - MS6) control pins. All optional functions of the MT9126 are pin selectable allowing a simple interface to industry standard codecs, digital phone devices and Layer 1 transceivers. Linear coded PCM is provided to facilitate external DSP functions .