Nortel Circuit Card, Installation Manual, Page: 395 / 908

NT6D80 MSDL card Page 395 of 906
Circuit Card Description and Installation
Equipment emulation mode – Configure an MSDL port to emulate DCE or
DTE by setting switches on the card and downloading LD 17 interface
parameters.
I/O port electrical interface – Each MSDL port can be configured as an
RS-232 or RS-422 interface by setting the switches on the MSDL card.
MSDL ports use Small Computer Systems Interface (SCSI) II 26-pin female
connectors.
Figure 84 on page 396 shows the system architecture using the MSDL as an
operational platform. It illustrates operation routing from the CPU, through
the MSDL, to the I/O equipment. It also shows an example in which DCH
operation peripheral software in the MSDL controls functions on ports
2 and 3.
MSDL operations
The system automatically performs self-test and data flow activities. Unless
a permanent problem exists and the system cannot recover, there is no visual
indication that these operations are taking place.
The system controls the MSDL card with software that it has downloaded.
The MSDL and the system enable the MSDL by following these steps:
1 When the MSDL card is placed in the system, the card starts a self-test.
2 When the MSDL passes the test, it indicates its state and L/W version to
the system. The CPU checks to see if downloading is required.
3 After downloading the peripheral software, the system enables the
MSDL.
4 MSDL applications (DCH, AML, SDI) may be brought up if
appropriately configured.