User's Manual

10-4 68P81093C75-A
The DSP and DSP ASIC perform the necessary digital signal
processing for the station audio and data signals. The DSP circuitry
interfaces with the Receiver Module (receive audio), the Exciter
Module (modulation signal), and the Wireline Interface Board
(wireline audio).
The 2.1 MHz Reference Oscillator generates the reference signal
used by the Receiver and Exciter Modules.
Wireline Interface
Board
Introduction
The Wireline Interface Board (WIB) serves as the interface between
the customer telephone lines and the station. In general, the WIB
processes and routes all wireline audio signals between the station
and the landline equipment (such as consoles, modems, etc.).
Landline-to-station and station-to-landline audio signals are
connected to the WIB via RJ-45 connectors on the top panel of the
station.
Wireline Interface
Board Operation
The WIB contains the following:
• A microprocessor
• Two FLASH memory ICs (which contain the WIB operating
software downloaded by the SCM)
• An ASIC device to process and route the various audio signals
Analog, SECURENET , and ASTRO signals are processed as follows:
• Analog signals are converted to digital signals and routed to the
Station Control Module via the Time Division Multiplex (TDM)
bus.
• ASTRO and ASTRO CAI data signals are processed by an ASTRO
modem card (the daughter board is plugged into the WIB) and
sent to/from the SCM via the HDLC bus. (The station operates
in transparent mode only, and does not perform encryption or
decryption of the ASTRO or ASTRO CAI signal.)
• SECURENET encoded signals are processed by the ASIC, sent
to/from the microprocessor via the data bus, and sent to/from the
Station Control Module microprocessor via the HDLC bus. (The
station operates in transparent mode only, and does not perform
encryption or decryption of the SECURENET signal.)
NOTE: The WIB is offered in the 4-wire configuration only.