Lantronix SCS Reference Manual page 165

Modems
Problem
All data is corrupted.
The first few lines of
data are transmitted
properly, but the
subsequent data is
corrupted.
When the port is logged
out, the modem doesn't
hang up the phone line.
When the phone is
hung up, the SCS
doesn't log out the port.
The modem answers,
but won't connect to the
remote modem.
Table 9-3: Modem Troubleshooting, cont.
Possible Cause(s)
The ground pins aren't wired
correctly.
The modem's serial speed does not
match the serial speed on the SCS
port used.
Flow control isn't working properly. Ensure that the modem and SCS port are configured
The modem is set to the wrong baud
rate.
Flow control isn't working properly. Ensure that the modem and SCS port are configured
The ground pins aren't wired
correctly.
Modem Control isn't enabled on the
SCS port used.
The DTR signal isn't attached.
The modem isn't configured to reset
when the DTR signal is dropped.
Modem Control isn't enabled on the
SCS port used.
The DCD signal isn't attached.
The modem isn't configured to
deassert DCD upon loss of carrier.
One or both modems are configured
not to connect unless some feature
is enabled (for example, error
correction).
The two modems cannot be
connected. (Some modems are
incompatible with one another.)
Remedy
Verify the wiring. Ensure that the ground pins on the
RJ45 ports are wired together.
Ensure that the serial speeds of the modem and SCS
port match.
to use the same flow control method.
Cycle power on the modem.
to use the same flow control method. Flow control
is discussed in detail in Flow Control on page 8-18.
Verify the wiring. On RJ45 ports, ensure that the
ground pins are wired together.
Ensure that Modem Control is enabled. See Define
Ports Modem Control on page 12-8 for details.
Verify the wiring. Ensure that the ground pins on
RJ45 ports are wired together.
Check the modem's configuration.
Ensure that Modem Control is enabled. See Define
Ports Modem Control on page 12-8 for details.
Verify the wiring. Ensure that the ground pins on
RJ45 ports are wired together.
Check the modem's configuration.
Check the documentation for both modems; verify
their configuration.
Replace one or both of the modems. Verify that the
modem is using the correct and current version of its
software.
9-17
Troubleshooting