MT88E46
Bellcore Compliant Calling Number
Identification Circuit
Advance Information
Features
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Compatible with Bellcore GR-30-CORE,
SR-TSV-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) detection is 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 8dB 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 5V
±
10% supply voltage
Uses 3.579545MHz crystal
Low power CMOS with power down mode
DS5350
ISSUE 1
March 2000
Ordering Information
MT88E46AS
20 Pin SOIC
-40 to +85
°
C
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CIDCW and CWD telephone adjunct boxes
Computer Telephony Integrated (CTI) systems
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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
hook and off hook - use different algorithms which
are optimized for the CPE states. In ‘off hook mode’
the CAS detector is Bellcore compliant when near
end speech is attenuated 8dB or better. ‘On hook
mode’ is optimized for talkdown only and typically
meets talkdown condition 1 (the average case)
without speech attenuation at Tip/Ring such as in the
on hook state MEI CPE.
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Applications
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Bellcore compliant CIDCW (Calling Identity
Delivery on Call Waiting) and CWD (Call
Waiting Deluxe) telephones
GS1
IN1+
IN1-
IN2+
IN2-
GS2
V
REF
Bias
Generator
+
-
PWDN
+
-
GS1en
FSK
Bandpass
GS1en
Anti-Alias
Filter
PWDN
PWDN
MODE
GS1en
FSKen CASen
Control Bit
Decode
2130Hz
Bandpass
2750Hz
Bandpass
CASen
On/Off Hook mode
Tone
Detection
Algorithm
FSKen
CASen
Carrier
Detector
FSK
Demod
MODE
Data Timing
Recovery
DATA
DCLK
CD
Mux
DR
DET
DR/DET
PWDN
Oscillator
Vdd
Vss
OSC1
OSC2
CB0 CB1 CB2
Patent pending
Figure 1 - Functional Block Diagram
1
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
