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Configuration Options
4-22
9820-A2-GB20-20
June 2000
Table 4-6. User Data Port Physical Interface Options (2 of 2)
Invert Transmit Clock
Possible Settings: Auto, Enable, Disable
Default Setting: Auto
Determines whether the clock supplied by the FrameSaver unit on interchange circuit
DB (ITU 114) – Transmit Signal Element Timing (DCE Source) TXC is phase inverted
with respect to the clock used to time the incoming Transmitted Data (TD).
Display Conditions
– This option does not appear for Model 9820-45M.
Auto – The port checks the clock supplied by the DCE on TXC. If necessary, the port
automatically phase inverts the clock with respect to the transmitted data.
Enable – Phase inverts the TXC clock. Use this setting when long cable lengths
between the FrameSaver unit and the DTE are causing data errors.
Disable – Does not phase invert the TXC clock.
Monitor DTR
Possible Settings: Enable, Disable
Default Setting: Enable
Specifies whether the state of the DTE Ready (DTR) circuit on the user data port will be
used to determine when valid data communication is possible with the DTE. When the
DTR off condition is detected, an alarm is generated, LMI is declared down, and no
further transfer of frame relay data can occur on this interface.
Display Conditions
– This option does not appear when Port Type is set to X.21 (the
signal is assumed to be asserted).
Enable – Interchange circuit CD (ITU 108/1/2) – DTR is monitored to determine when
valid data is sent from the DTE.
Disable – DTR is not monitored. DTR is assumed to be asserted and data is being
transmitted, regardless of the state of the lead.
Monitor RTS (Control)
Possible Settings: Enable, Disable
Default Setting: Enable
Specifies whether the state of the Request To Send (RTS) circuits on the user data port
will be used to determine when valid data communication is possible with the DTE.
When the RTS off condition is detected, CTS is deasserted, LMI is declared down, and
no further transfer of frame relay data can occur on this interface.
Display Conditions
– This option does not appear for Model 9820-45M.
Enable – Interchange circuit CA (ITU 105) – RTS is monitored to determine when valid
data communication is possible with the DTE.
Disable – RTS is not monitored. RTS is assumed to be asserted and data is being
transmitted, regardless of the state of the lead.
Port (DTE) Initiated Loopbacks
Possible Settings: Local, Disable
Default Setting: Disable
Allows a local external DTE Loopback to be started or stopped via the port’s attached
data terminal equipment using the port’s interchange lead LL (ITU 141) for Models
9802, 9820-2M, and 9820-8M, or LA (ITU 143) for Model 9820-45M.
Display Conditions
– This option does not appear when Port Type is set to X.21.
Local – The DTE attached to the port controls the local external DTE Loopback.
Disable – The DTE cannot control the local external DTE Loopback.