MT89L85 Datasheet, PDF (8/20 Pages) Mitel Networks Corporation – CMOS ST-BUS™ FAMILY Enhanced Digital Switch

MT89L85
Advance Information
During the microprocessor initialization routine, the
microprocessor should program the desired active
paths through the matrices, and put all other
channels into the high impedance state. Care should
be taken that no two connected ST-BUS outputs
drive the bus simultaneously. When this process is
complete, the microprocessor controlling the
matrices can bring the ODE signal high to relinquish
high impedance state control to the CMH_b0s.
Applications
Typical Exchange, PBX or Multiplexer
Figure 7 shows a typical implementation of line cards
being interconnected through a central routing matrix
that can scale up in channel capacity to
accommodate different number of ports depending
on the application. In a configuration where the
switched services utilize concatenated or grouped
time slots to carry voice, data and video (channels of
128, 256 Kb/s, ISDN H0 and others), the central
routing matrix has to guarantee constant throughput
delay to maintain the sequence integrity between
input and output channels. Figure 7 shows an
example where the MT89L85 device guarantees
data integrity when data flows from the T1/E1 to the
S/U interface links and vice-versa. Modern
technologies available today such as Frame Relay
network using dedicated fractional T1 are one of the
key applications for the MT89L85 device.
Low Latency Isochronous Network
In today's local working group environment, there is
an increasing demand for solutions on
interconnection of desktop and telephone systems
so that mixed voice, data and video services can be
grouped together in a reliable network allowing the
deployment of multimedia services. Existing
multimedia applications require a network with
To other lines
Basic Rate Line Card
MT8930/31
S/U
MT8910
ST-BUS
Layers
C
2&3
Entity
P
U
ST-BUS
MT8972
To other lines
ROUTING
MATRIX
MT89L85’s
MT8940/
MT8941
ST-BUS
MH89760/
MH89790
T1/E1
Link
MT8920
µC
Primary Rate Card
Figure 7 - Typical Exchange, PBX or Multiplexer Configuration
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