T E L C O / B L A C K D I G I Ta L O P E R At I O N; R E D A N A L O G / D I G I Ta L V O I C E O P E R A T I O N - Motorola STU-III/R Operation, Installation, And Maintenance Manual

T E L C O / B L A C K D I G I T A L O P E R A T I O N
The STU-III/R can be operated over most TELCO networks using
the integral wireline interface and wireline modem. The TELCO
connection is made via the TELCO connector (J6) on the back panel
of the STU-III/R (see Chapter 3).
Alternatively, the STU-III/R can operate on ablack digital network.
This network can take many forms, but typically consists of an HE
radio link. For this type of installation, an external HE modem is
connected to the STU-III/R black digital connector (J5) and to an HE
radio to provide the communication link. Black digital operation is
limited to 2400 bps.
R E D A N A L O G / D I G I T A L V O I C E O P E R A T I O N
The STU-III/R can be used in astandard telephone configuration by
connecting apowered handset to the four-wire analog voice interface
on the RCI connector (J4). This is referred to as red analog voice
operation. Alternatively, the STU-III/R can operate in the red
digital voice configuration. In this configuration, unencrypted
digital vocoder frames are transmitted and received over the red
digital connector (J3). Red digital operation is typically used to
create asecure conference call with little or no signal degradation. _
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