Page514 of 544 NTAK93D-channel handler interface
553-3011-100 Standard14.00 January 2002
Overview
The NTAK93 provides D-channel handler interfaces required by the ISDN
PRI trunk. It performs D-channel layer 2 message processing and layer 3
preprocessing. It is a daughterboard that mounts to the NTAK09 1.5 Mb DTI/
PRI card or NTBK50 2.0 Mb PRI card using standoff reference pins and
connectors.
Features and functions
NTAK93 provides the following features and functions:
•D-channel or DPNSS interface
•special features included for LAPD implementation at DCH:
—system parameters are service changeable (system parameter s are
downloaded from software)
—incoming Layer 3 message validation procedures are implemented
in the D-PORT firmware
—supported message units and information elements may be service
changed
—translation of the CCITT message types information elements into a
proprietary coding scheme for faster CPU operation
—convention of IA5-encoded digits to BCD-encoded digits for
incoming layer 3 messages for faster CPU operation
—self-test
—loopback
Physical description
The DCH function can be located in the main and IP expansion cabinets. The
DTI/PRI card which carries a DCH daughterboard resides in the main and IP
expansion cabinets.