COMSPHERE 3550 Series Data Service Units
4-20 December 1996 3550-A2-GB20-20
Table 4-7
Lead States
Symbol Meaning
Off (below text line)
ON (above text line)
Changing
?Indicates an illegal value
NOTES:
Input leads A and B:
Off (
) when voltage on lead is less than +.8V.
ON (
) when voltage on lead is more than +2.2V.
Output leads are either ON or Off:
When output is set to Off (
), –12V is applied to lead.
When output is set to ON (
), +12V is applied to lead.

Reporting External Lead Changes to NMS

Changing either the
output leads
or the
input leads
changes the DSU’
s health and status message.
If the DSU is polled by the 6700 Series NMS, the NMS
reports a change configuration notification (CCN) event.
The NMS operator can then issue a
CCN Display
command to determine what caused the event.
•
If the CCN event was caused by a change in the
external leads
, select
Displ
(F1) to see the current
states of the leads.
•If a positive (+) voltage is detected in either one of
the
input leads
, an external leads alarm is also
reported.
Messages Branch
The
Messages (
Msgs) branch of the top-level menu
allows the DSU to receive messages from the NMS. It
only appears when there is a message waiting. Both
control and tributary DSUs can receive messages.
T
o receive messages:
.Procedure
1.
Press the
F3
key (Msgs).
2.
Select
Read (F1).
3.
If the message is
less than
16 characters in length,
the entire message is displayed.
If the message is
gr
eater than
16 characters, press
the key to scroll additional lines of the
message onto the screen.
T
o clear (delete) messages:
.Procedure
1.
Press the
F3
key (Msgs).
2.
Select
Clear (F2).
The message is deleted, and
Msgs no longer
appears over the F3 key.