Merlin 3070 Service And Maintenance Manual page 7

CONTROL UNIT
The control unit provides power for all voice terminals and most accessories. All outside lines
and all voice terminals and telephones connect to the control unit, which contains the
microprocessor and modules for all the advanced features available with the MERLIN system.
Model 1030 consists of a basic control unit (A). Behind the removable front panel (B) of the
control unit, the modules (C) are arranged vertically across the width of the unit. Each vertical
position serves the particular function defined on the colored band on the base (D). Tabs (E)
on the individual modules are color-coded to the appropriate positions. Module positions in
the basic control unit are numbered on the colored band (from left to right) I through I5.
Positions reserved for optional features and services may be vacant and will have protective
plastic covers.
In Model 3070, an expansion unit (F) is mounted on top of the control unit. Additional
modules, located behind the removable front panel of the expansion unit, increase the
capacity of the system to up to 30 lines and 70 voice terminals or telephones. Module
positions in the expansion unit are numbered 16 through 28. Wiring connecting the two units
runs inside the cabinets behind the modules.
Modules are electrically connected to the control unit via pins located at the rear of the module
slots. Abrupt insertion or removal of modules may cause pins to bend, triggering problems
within the control unit. (For any problem common to several voice terminals, it is advisable to
examine the pins.)
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