363-206-295
Operations Interfaces
6-6
Issue 1
December 1997
In a bay multiple CIT cabling arrangement, connecting a CIT to any shelf in the
bay provides CIT access to that DDM-2000 shelf and any other DDM-2000 OC-3
or OC-12 Multiplexer shelf in that bay. The shelf is selected by using the shelf ID
login. In this arrangement, only one front and one rear CIT access can be used.
Also with this arrangement, access to shelves in multiple subnetworks can be
achieved from the same physical interface. A subnetwork consists of all shelves
interconnected with the SONET DCC over OC-N interfaces.
For example, with 6 shelves per bay and 8 bays in a subnetwork, access to 48
shelves is achieved with a single physical interface.
Using a PC as a CIT
6
In addition to CIT functions, a PC is required for software downloads and
facilitates software program updates. Any
MS-DOS PC can be used to emulate a
traditional CIT through a variety of low-cost terminal emulator software packages;
thus, an
MS-DOS PC can serve DDM-2000 OC-12 Multiplexer needs very
efficiently. In addition, the DDM-2000 OC-12 Multiplexer user interface can be
accessed from within
Windows
*
(Version 3.0 or later) on an
MS-DOS PC.
The DDM-2000 OC-12 Multiplexer uses flash erasable program memory
(EPROM) devices that can be upgraded through direct download from an
MS-
DOS PC. Upgrades are made available through the distribution of floppy disks
compatible with the recommended PCs.
Modem Access
6
The rear access CIT interface (CIT 2) is configured as DTE to allow a permanent
modem connection without requiring a null modem. However, a null modem is
required when connecting a CIT directly to the rear access DTE interface. CIT
access via a modem connection is identical to local CIT access. Automatic
selection (autobaud detection) data rates of 1200, 2400, 4800, 9600, and 19,200
baud are provided for both CIT interfaces.
NOTE:
The DDM-2000 OC-12 Multiplexer CIT interface supports data rates up to
19,200 baud but does not provide flow control. Some terminals and PCs
when set for higher data rates will not work properly at these rates with
equipment like the DDM-2000 OC-12 Multiplexer that does not provide flow
control. The system may appear to stop working when reports or long
prompts are displayed. If this happens, try setting the terminal to a lower
data rate. The data rate of the DDM-2000 OC-12 Multiplexer is
automatically set to match the data rate of the terminal (autobaud).
*
Registered trademark of Microsoft Corporation.
