Specifications

X723-300151 5-16 Issue 2
momentarily on the host equipment and also on equipment connected to
the host.
2 Terminal.
This will isolate line 1 from line 2 providing two separate PCM paths to
the cross connect switch. Signalling may be different on line 1 and line 2
(CAS or CCS) and fault logging may be individually set as for multipoint.
In terminal mode, the mapping of PCM timeslots to the backplane
streams is fixed. The selection of ‘TS Assign’ menu is inhibited, and user
will be warned that this option is ‘Not available in this mode’.
In port 1, line 1 is connected to backplane stream s1, line 2 to s2. In port
2, line 1 is connected to backplane stream s3, line 2 to s4. In all cases
PCM timeslots 1, 2, 3,....31 are connected to backplane stream timeslots 1,
2, 3,....31.
3 A/B Switching.
This mode is designed to change from one line to another upon a specific
line failure. All timeslots for both outgoing line streams will be sourced
from the relevant stream (S1 for port 1 or S3 for port 2) and all timeslots
from the active line signal will be connected to the relevant stream as
indicated below. The mapping of PCM timeslots to the backplane streams
is fixed with TS1, 2, 3,....31 of the backplane stream. The selection of ‘TS
Assign’ menu is inhibited, and user will be warned that this option is ‘Not
available in this mode’.
The operator can set the following options:
i) Signalling mode
This must be the same for both PCM streams; either CAS or CCS.
ii) Switch over delay (Fault Persistency)
This delay parameter will be used to inhibit change-over of the
PCM source until the PCM fault has been present for the delay
period.
iii) Hold delay
This parameter will be used to disable operation of the switch over
facility immediately after a change-over. The facility will be re-
enabled after the delay period has expired.
Note: Both the switch over delay timer and the hold delay timers
run in parallel and not consecutively therefore the hold delay must