3 – Installation & Wiring ACS-160 Series & STL-160 Series T1 Multiplexer Installation & Operation
Version 2.11, August 2011
Harris Corporation 3-7
Intraplex Products
SW1 on the MA-215 or MA-217B adapter performs these functions:
● RS-485 remote port bias
● RS-485 remote port termination
● External timing input impedance
● Optional delay input impedance
The positions of the SW1 DIP switches (Figure 3-7) control the functions. Table 3-3 lists the switches
and their functions.
Table 3-3. MA-215/MA-217B SW1 Switches and Functions
Switch
Factory
Default Description
1 and 2 On These two switches control the RS-485 bias of the remote port (used for remote ports in daisy
chain configuration). These switches normally should be in the On (bias) position. When daisy
chaining, one module adapter in the chain should have these switches on, and the others
should be off.
3 On This switch controls the termination impedance (120 ohms) for the RS-485 portion of the
remote port. This switch should normally be in the On position. When daisy chaining, the last
multiplexer in the chain should have this switch on, and the others should be off.
4 On This switch controls the external timing input impedance (120 ohms; TIMING IN port). This
switch is normally set to on. When daisy chaining, the last multiplexer in the chain should have
this switch On, and the others should be off.
5 On This switch controls the input impedance (120 ohms) when using the optional time delay
capability. It is normally set to On.
6 On Not used
3.5.2 MA-235-1 and MA-235-2 Module Adapters
An external shielded cable connects the MA-235-1 and MA-235-2 module adapter pair. The adapters
operate in line redundancy with a pair of CM-5RB modules. The module adapters are implemented
separately to allow replacement of a failed adapter without interruption of service. The MA-235-1
adapter is the Primary Module Adapter and the MA-235-2 adapter is the Backup Module Adapter in line
redundancy applications. Each has an RJ-48 T1 interface with channel service unit (CSU) protection.
The combined adapters in both common modules bridge timing in and serial I/O connectors. A single
timing out connector is provided and connected to the currently active common module. Timing in and
timing out signals are transmitted on separate RJ-11 connectors. Table 3-4 gives MA-235-1 input and
output port assignments, Table 3-5 gives MA-235-2 input and output port assignments, and Figure 3-
8 shows connector locations. An external removable shielded cable (CA-202, 26-pin miniature Sub-D)
provides signal connection between the MA-235-1 and MA-235-2 adapters.
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