ADC UTU-701C User Manual

The G.703 interface performs the following functions:

provides a jumper-selectable 75 or 120 

Ω

 DTE interface (see 

 for jumper 

locations)

allocates full or fractional portion of the total 2048 kbps bandwidth to and from the G.703 interface

frames data according to G.704

inserts an idle code into unused time slots at the G.703 output

recovers timing from the received G.703 signal

monitors multiframe CRC-4 errors in the received G.703 signal 

regenerates multiframe (CRC-4) code at the G.703 output

regenerates time slot 0 at the G.703 output

transports time slot 16 transparently between G.703 ports

The G.703 interface operates in the structured application mode when less than 32 time slots are selected and in 
the unstructured mode when 32 time slots are selected (see 

 on 

). These modes are 

described in detail in the 

.

The HDSL interface includes the HDSL framer, which performs HDSL multiplexing and demultiplexing; 
a firmware-controlled programmable clock, which sets the HDSL line rate at the interface output; and the 
transceiver and line-interface circuits for the single HDSL pair.

In the transmit direction, the HDSL framer accepts inputs from the G.703 data port as shown in 

. The data 

is placed on the HDSL pair along with the HDSL overhead bits for presentation to the transceiver. A clock 
representing the selected HDSL line rate is introduced to the transceiver, which outputs data on the single-pair 
HDSL line. In the receive direction, overhead bits are stripped and processed, and time slots are output to the 
G.703 interface.

Reversals of Tip and Ring wires are automatically detected and accommodated. The Monitor HDSL Span screen 
indicates if the Tip and Ring wires are reversed.

The UTU and ETU units can synchronize to any one of the following timing sources:

G.703: Timing recovered from G.703 input signal

EXT: External 2.048 MHz reference (available only for UTUs in a shelf with a management unit installed)

This device runs a program which in real-time:

monitors the HDSL framer performance

responds to user requests

maintains a history of system performance