MT89L80AN1 ZARLINK [Zarlink Semiconductor Inc], MT89L80AN1 Datasheet - Page 8

• Manufacturer Part Number: MT89L80AN1
• Description: CMOS ST-BUSTM Family
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

of the line circuit by building signalling logic, e.g., for on-off hook detection, which communicates on an ST-BUS
output. This signalling ST-BUS output is monitored by a microprocessor (not shown) through an ST-BUS input on
the bottom MT89L80.
Fig. 8 shows how a simple digital switching system may be designed using the ST-BUS architecture. This is a
private telephone network with 256 extensions which uses a single MT89L80 as a speech switch and a second
MT89L80 for communication with the line interface circuits.
Figure 7 - Example of Typical Interface between 89L80s and 8964s for Simple Digital Switching
Controlling
Processor
Micro-
89L80 used
89L80 used
control and
in message
signalling
mode for
speech
switch
as
Figure 8 - Example Architecture of a Simple Digital Switching System
MT89L80
MT89L80
Signalling
Control &
Speech
Switch
89L80
89L80
-
-
STo0
STo0
STi0
STi0
STo0-7
Zarlink Semiconductor Inc.
8
STi0-7
MT89L80
8
STo0-7
8
System
8
STi0-7
8
with Codec (e.g. 8964)
with Codec (e.g.8964)
Line Interface Circuit
Line Interface Circuit
Line Interface Circuit with 8964 Filter/Codec
D
D
D
Repeated for Lines
X
R
C
2 to 255
Filter/Codec
•
•
•
Signalling
MT8964
Logic
Line 256
Line 1
Line Driver
Converter
2- to 4-
Wire
and
Repeated for Lines
2 to 255
Data Sheet
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•
•