Chapter 3. Operation
Remote Line Loopback | Local Line Loopback | Local DTE Loopback |
NxT1 HSSI
T1 Interfaces | IMUX | DTE |
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Figure 3-4. HSSI Interface Loopback Test Diagram
LA AND LB
(Not applicable in V.35 mode.)
Displays the status of the loopback circuit A and B signals. LA and LB are asserted by the DTE to enable a loopback on the DCE and its associated data communications channel. Four possible loop- back options are available:
LA | LB | Loopback |
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Off | Off | No Loopback Active |
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On | On | Local DTE Loopback is Active |
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On | Off | Local Line Loopback is Active |
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Off | On | Remote Line Loopback is Active |
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TA
Displays the status of the data Terminal equipment Available signal. TA will be asserted by the DTE (independently of CA) when the DTE is prepared to both send and receive data to and from the DCE. Valid data transmission should not commence until CA has also been asserted by the DCE. If the data communications channel requires a keep alive data pattern when the DTE is disconnected, then the DCE shall supply this pattern while TA is deasserted.
When using the NxT1 HSSI Module (1200346L2 only) in V.35 mode, TA displays the status of the Request to Send (RTS) signal. When RTS is active in a V.35 configuration, Clear to Send (CTS) is also active.
NxT1 HSSI/V.35 Module User Manual | 37 |
