MT90820 Datasheet, PDF (24/37 Pages) Mitel Networks Corporation – CMOS ST-BUS™ FAMILY Large Digital Switch (LDX)

MT90820
Data Sheet
The MT90820 is designed to accept a common frame pulse F0i, the 4.096 MHz and 16.384 MHz clocks required by
the HMVIP standards. To enable the Width Frame Pulse Frame Alignment Mode, the WFPS pin has to be set to
HIGH and the DR1and DR0 bits set for 8.192 MB/s data rate operation.
Digital Access Cross-Connect System
Figure 7 illustrates how the MT90820 can be used to construct, for example, a 256 E1/T1 digital access cross-
connect system (DACS). The system consists of 32 trunk cards each having eight E1 or T1 trunk interfaces for a
total of 256 trunks. The central switching block is constructed from 16 MT90820 devices.
Figure 8 shows how an 8,192 x 8,192 channel switch can be constructed from 4,096 x 4,096 channel switch
modules. Figure 5 shows the implementation of the 4,096 x 4,096 channel switch modules from four MT90820
devices. Therefore, 16 MT90820 devices are required to realize an 8,192 x 8,192 non-blocking switch module with
64 input and 64 output streams. Each stream has 128 channels per frame for a data rate of 8.192 Mb/s.
Figure 9 shows an eight-stream trunk card block diagram. The MT8986 Multi-rate Digital Switch are used to
concentrate the 32-channel 2.048 Mb/s ST-BUS (DSTi and DSTo) streams at each E1/T1 trunk onto four 128-
channel 8.192 Mb/s streams.
It will take 256 MT8986 devices to implement the switching matrix of using 32-channel 2.048 Mb/s ST-BUS streams
in a square (16 x 16) configuration. A large saving in component cost and board area can be achieved by using
128-channel 8.192 Mb/s streams. That is, the same capacity can be achieved using 64 MT8986 devices + 16
MT90820 devices for a total of 80 devices.
Trunk Card (TC) 0
E1₀
128 channels at 8.192 Mb/s
8 x E1/T1
E1₇
Trunk Card
TC1
E1₈
8 x E1/T1
E1₁₅
Trunk Card
E1₂₄₇
E1₂₅₅
TC31
8 x E1/T1
Trunk Card
64 input streams
x
64 output streams
8,192 x 8,192 channel
Switch Matrix
Sixteen MT90820
operate
in 8 Mb/s mode
(Figure 9)
Figure 7 - 256 E1/T1 Digital Access Cross-Connect System (DACS)
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