Nortel Networks Circuit Card - Manual (Page 783)

NTBK50 2.0 Mb PRI card Page 783 of 906
Circuit Card Description and Installation
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 with respect to 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
• receive clock output
• transmit clock output
The receive and transmit clocks can be of slightly different bit rates from each
other as determined by the transmit and receive carrier clocks.
The NTBK50 supports a D-Channel Handler Interface (DCHI)
daughterboard. It is equivalent to a single port of an NTAK02 SDI/DCH card.
The NTBK50 also supports a Downloadable D-Channel Handler interface
(DDCH) daughterboard. The DDCH brings MSDL D-channel capability to
the system.
DCHI Configuration for NTAK93 only (SW1)
The NTAK93 DCHI daughterboard can be operated in two separate modes
defined by an on-board dip switch. It can operate in a standard DCHI mode
common to most ISDN standard countries. It can also operate in a DPNSS