Description
The MT88E46 is a CMOS integrated circuit suitable for receiving the FSK and CAS signals in North American (Bellcore) CIDCW, CWD and CID (Calling Identity Delivery) services. It provides an optimal solution for the CIDCW (also known as Type 2) and CWD (Type 2.5) telephone set applications by providing separate input op amps for Tip/Ring and 4-wire side (receive pair of the telephone hybrid or speech IC) connections. The Tip/Ring connection is compatible with TIA’s MEI scheme and can be used for FSK demodulation and ‘on hook mode’ CAS detection. The 4-wire side connection is for ‘off hook mode’ CAS detection. The CAS detection modes - on

FEATUREs
• Compatible with Bellcore GR-30-CORE, SRTSV-002476; TIA/EIA-716 and TIA/EIA-777
• Pin compatible with MT88E45
• Differential input amplifiers with adjustable gains for Tip/Ring and 4-wire side connections
• TIA (Telecommunications Industry Association) MEI (Multiple Extension Interworking) compatible architecture: CAS (CPE Alerting Signal) detectionis selectable between Tip/Ring and 4-wire side
• 4-wire side CAS detection is Bellcore talkoff and talkdown compliant when near end speech is attenuated 8 dB or better, and is close to talkoff compliant even without near end speech attenuation
• Tip/Ring side CAS detection typically meets talkdown condition 1 (the average case)
• 1200 baud Bell 202 and CCITT V.23 FSK demodulation
• Selectable 3-wire FSK data interface (serial bit stream or 1 byte buffer) with facility to monitor stop bit for framing error check
• FSK carrier detect status output
• 3 to 5 V ± 10% supply voltage
• Uses 3.579545 MHz crystal
• Low power CMOS with power down mode Applications
• Bellcore compliant CIDCW (Calling Identity Delivery on Call Waiting) and CWD (Call Waiting
Deluxe) telephones
• CIDCW and CWD telephone adjunct boxes