®
ISO-CMOS ST-BUS™ FAMILY
MT8976
T1/ESF Framer Circuit
Features
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D3/D4 or ESF framing and SLC-96 compatible
2 frame elastic buffer with 32
µsec
jitter buffer
Insertion and detection of A, B,C,D bits.
Signalling freeze, optional debounce
Selectable B8ZS, jammed bit (ZCS) or no zero
code suppression
Yellow alarm and blue alarm signal capabilities
Bipolar violation count, F
T
error count, CRC
error count
Selectable robbed bit signalling
Frame and superframe sync. signals, Tx and Rx
AMI encoding and decoding
Per channel, overall, and remote loop around
Digital phase detector between T1 line & ST-
BUS
One uncommitted scan point and drive point
Pin compatible with MT8977 and MT8979
ST-BUS compatible
ISSUE 9
May 1995
Ordering Information
MT8976AC
28 Pin Ceramic DIP
MT8976AE
28 Pin Plastic DIP
MT8976AP
44 Pin PLCC
-40°C to 85°C
Description
The MT8976 is Mitel’s second generation T1
interface solution. The MT8976 meets the Extended
Super Frame format (ESF), the current D3/D4 format
and is compatible with SLC-96 systems.
The MT8976 interfaces to DS1 1.544 Mbit/sec digital
trunk.
Applications
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DS1/ESF digital trunk interfaces
Computer to PBX interfaces (DMI and CPI)
High speed computer to computer data links
C1.5i
ST-BUS
Timing
Circuitry
2 Frame
Elastic Buffer
with Slip
Control
DS1
Link
Interface
2048-1544
Converter
CSTi0
CSTi1
CSTo
Serial
Control
Interface
ABCD
Signalling RAM
XCtl
XSt
Control Logic
E1.5i
Phase
Detector
DS1
Counter
RxFDLClk
RxFDL
RxA
Remote &
Digital
Loopbacks
RxB
TxA
TxB
TxFDLClk
TxFDL
RxD
TxSF
C2i
F0i
RxSF
DSTo
DSTi
Data
Interface
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E8Ko
V
SS
V
DD
Figure 1 - Functional Block Diagram
4-29
MITEL [ MITEL NETWORKS CORPORATION ]
