Service manual

1-10 Description: Functional Theory of Operation
1.3.4 Wireline Module Operation
1.3.4.1 Introduction
The wireline module serves as the interface between the analog telephone lines and the analog
signals of the station. The wireline module supports both 2-wire and 4-wire configurations. In
general, the wireline processes and routes all wireline audio signals between the station and the
landline equipment (such as consoles). Landline-to-station and station-to-landline audio signals are
connected to the wireline via copper pairs at the rear of the station.
1.3.4.2 Wireline Module Operation
Wireline board is used to connect an analog audio source and sink (such as a console) to the base
station/repeater. The wireline uses an on-board FPGA to perform various DSP audio processing
functions such as tone remote control, filtering, wireline squelch, and echo cancellation.
On the wireline board, audio is converted from the analog domain to the digital domain by a CODEC.
The FPGA can then process the digital audio before sending the data back to the CODEC to be
converted back to analog. Both the Tx and Rx path are processed by the FPGA in this way. Audio
enters and leaves the wireline board as analog.
Rx Audio represents data received over-the-air by the base station/repeater's receiver module. Tx
Audio is analog audio that originates from a remote location that is to be broadcast over-the-air by
the station's transmitter. A single 2-channel (stereo) CODEC is used to perform the A/D and D/A
conversions.
The wireline board provides the connection to an analog audio source/sink (such as a console) to the
MTR3000 Base Station/Repeater. Specifically, the wireline board provides for the following:
• Tone Remote Control
• DC Remote Control
• Analog Voting
• 4-wire balanced audio connection
• 2-wire balanced audio connection
See Figure 1-7 for the Wireline block diagram.