®
CMOS
MT8843
Calling Number Identification Circuit 2
Preliminary Information
Features
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Compatible with British Telecom (BT) SIN227 &
SIN242, Cable Television Association (CTA)
TW/P&E/312, and Bellcore TR-NWT-000030 &
SR-TSV-002476
Ring and line reversal detection
Bellcore "CPE Alerting Signal (CAS)" and BT
"Idle State Tone Alert Signal" detection
1200 baud BELL 202 and CCITT V.23
Frequency Shift Keying (FSK) demodulation
High input sensitivity
Dual mode 3-wire data interface
Low power CMOS with powerdown mode
Input gain adjustable amplifier
Carrier detect status output
Uses 3.58 MHz crystal or ceramic resonator
BT Calling Line Identity Presentation (CLIP),
CTA CLIP, and Bellcore Calling Identity Delivery
(CID) systems
Feature phones, including Analog Display
Services Interface (ADSI) phones
Phone set adjunct boxes
FAX and answering machines
Database query and Computer Telephony
Integration (CTI) systems
ISSUE 1
February 1995
Ordering Information
MT8843AE
24 Pin Plastic DIP
MT8843AS
24 Pin SOIC
-40 °C to +85 °C
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Description
The MT8843 Calling Number Identification Circuit 2
(CNIC2) is a low power CMOS integrated circuit
intended for receiving physical layer signals
transmitted according to BT (British Telecom)
SIN227 & SIN242, CTA (Cable TV Association) TW/
P&E/312 and Bellcore TR-NWT-000030 & SR-TSV-
002476 specifications.
The CNIC2 provides all the features and functions
offered by Mitel’s MT8841 (CNIC), including 1200
baud BELL 202 and CCITT V.23 FSK demodulation.
The 3-wire serial FSK interface provided by CNIC
has been enhanced to operate in two modes. The
first mode is the CNIC compatible mode whereby
data transfer is initiated by the device. The new,
second mode allows a microcontroller to extract 8-bit
data words from the device. Furthermore, CNIC2
offers Idle State Tone Alert Signal and line reversal
detection capability for BT’s CLIP, ring burst
detection for CTA’s CLIP, and ring detection for
Bellcore’s CID.
Applications
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FSKen
IN+
IN-
GS
+
-
MODE
DCLK
DATA
DR
Anti-alias
Filter
FSK Bandpass
Filter
FSK
Demodulator
Data Timing
Recovery
To internal
cct.
VRef
CAP
PWDN
Bias
Generator
Carrier
Detector
Interrupt
Generator
Alert Signal High
Tone Filter
CD
INT
To internal cct.
Alert Signal Low
Tone Filter
Oscillator
Tone
Detection
Algorithm
Guard
Time
StD
St/GT
ESt
VDD
VSS
OSCin OSCout TRIGin
TRIGRC
TRIGout
Figure 1 - Functional Block Diagram
5-21
MITEL [ MITEL NETWORKS CORPORATION ]
