Model 458-SM-2-16 Transparent Switching Module
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2.0 Description
2.1 General
Description
The Model 458-SM-2-16 Transparent Switching Module (referred to as the Switching Module throughout this document)
is a transparent, electronically neutral multiplexing device that allows up to sixteen incoming lines to share (be directed
to) one or two independent output channels.
The Switching Module is bi-directional and does not contain active electronic components in the signal path between
input and output connectors. Therefore, it may be used in the reverse direction as a demultiplexer to direct one channel to
one of sixteen independent lines, or two independent channels to one of eight independent lines.
A high-level block diagram of the Model 458-SM-2-16 as a Multiplexer connected to a Telebyte Line Simulator (Local
Loop Simulator) is shown in Figure 1. The Matrix Block switching is accomplished by double coil state-stable ‘latch’
relays that are powered and switched by logic commands generated by the firmware interface to select or change the input
to output paths. The Telebyte Line Simulators use the same state-stable relays to allow the selection of line lengths for
each of its various Channels. Therefore, the loss of power to the Switching Modules and Line Simulators do not change
settings allowing the Switching Modules and Line Simulators to continue functioning during power loss and at power
recovery at its last setting.
The 458-3SLA (3-Slot) Chassis shown on the front cover would utilize one Switching Module with each Line Simulator,
which allows the various input signals to be selected by the Module and provided to the input Channels of the Line
Simulator. However, the Switching Module may be used alone or in any mixed combination, and located in any desired
slot of the chassis enclosure.
Figure 1 shows a high-level block diagram of the Model 458-SM-2-16
