Nortel Networks 553-3001-211 Cept transceiver, Slip control, Channel support interface, Loopbacks

Page 744 of 894 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.

Transmitter functions

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.

Loopbacks

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.

CEPT transceiver

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

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

D-channel support interface

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

553-3001-211 Standard 2.00 September 2004