Nortel Networks Circuit Card Manuale Utente

 NTAK79 2.0 Mb PRI card

requirements of the CCITT recommendation G.742. This provides jitter 
attenuation increasing from 0 dB to 60 dB over the frequency range from 
about 6 Hz to 6 KHz. 

The transmitter takes the binary (dual unipolar) data from the PCM 
transceiver and produces bipolar pulses which conform to the CCITT 
recommendation G.703 pulse shape.

The remote loopback function causes the device to transmit the same data that 
it receives, using the jitter attenuated receive clock. The data is also available 
at the receive data outputs. Local loopback causes the transmit data and clock 
to appear at the receive clock and data outputs. This data is also transmitted 
on the line unless transmit AIS is selected.

The transmitter and receiver functions are used for synchronization, channel, 
and signal extraction. The functions meet applicable specifications of the 
CCITT recommendation G.703 and G.732.

The transceiver provides transmit framing based on the 2.048 MHz clock 
derived from the DS-30X system clock and 1 KHz framing pulse.

Slip control provides organized recovery of PCM when the clock recovered 
from the external facility is at a different frequency than the local clock.

The D-channel support interface is a 64 Kbps, full-duplex serial bit stream 
configured as a DCE device. The data signals include: 

•

Receive data output 

•

transmit data input