Overview
150-357-200-02, Issue 2
8
February 9, 1999
HXU-357 List 1
Interfaces
Address/Data Bus
A bidirectional data bus controls the transfer of data to and from the
microprocessor in response to the state of the read/write control line.
The alarm inputs to the HXU-357 multiplexer card enter at the data bus.
When an alarm signal is received, the corresponding alarm LED on the front
panel of the HXU-357 illuminates. The HXU-357 sends independent alarm
signals to activate critical (CR), major (MJ), minor (MN), and far-end (FE)
alarm relays on the HMU-319 List 7 or List 7A management unit.
HiGain Management Unit Interface
The multiplexer card interfaces with the HMU over a serial RS-232 interface.
The HMU provisions the system parameters (for example, setting the BER
threshold), performs maintenance tasks, and monitors system status.
DS1 Interface
The DS1 signals enter the HXU as balanced, half-width bipolar waveforms
where they are converted to DS1 NRZ data and clock signals by the T1 Line
Interface Unit (LIU). (See
.) The LIU also provides BPV
detection and loopback functions.
Signals transmitted by the HXU are converted back to bipolar DSX-1 before
they are presented to the 28 Tip and Ring interfaces on the card.
The Line Protection block provides high-voltage protection and a line
protection switch.
