Operating the DSU
Control Branch
The Control (Ctrl) branch allows you to enable or disable the DSU's transmitter, as well as the DBM's, and to display or change the status of the general purpose external DTE leads. A DBM can be disabled if it is addressed from the Remote branch.
LEDs
The LEDs selection is only available from the Local branch. This selection allows you to monitor the port at any given time. When selected, the port's lead activity is reflected in the DCP circuit designation status indicators (TXD, RXD, etc.) on the faceplate of the Model 3616 DSU, or on the DCP of the Model 3615 DSU.
Transmitter Control
The Transmitter Control (TxCtl) selection allows you to enable or disable the DSU's or DBM's transmitter (DDS core).
When the DSU transmitter is disabled, the following is possible:
•When a DSU is disabled, it responds to tests. Aborting a test clears the test but the unit remains disabled.
•A DSU in test clears the test when a disable (or enable) command is received.
•If an enable command is executed to a control from the NMS or the local DCP, all disabled tributaries are enabled; all tributaries in test are restored to Data mode.
When the local DBM is disabled, the DBM does not originate or answer any calls until enabled.
External Leads
The External Leads (ExtL) selection allows you to display the state of four
When the configuration option Ext Leads (External Leads) is set to ExtLd (DBM Port option set), you can change the state of the two output leads from the DCP or NMS. When CCN by EL (CCN by External Leads) is enabled (DBM Port option set), the control DSU reports changes in the four leads to the NMS as part of its health and status poll response.
Table
Table
Lead States
Symbol | Meaning |
Off (below text line)
ON (above text line)
Changing
?
Indicates an illegal value
NOTES:
Input leads A and B:
Off ( |
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| ) when voltage on lead is less than +.8V. |
ON ( |
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| ) when voltage on lead is more than +2.2V. |
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Output leads are either ON or Off:
When output is set to Off ( |
|
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| ), ±12V is applied to lead. |
When output is set to ON ( |
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| ), +12V is applied to lead. |
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December 1996 |
