3Com AccessBuilder 980/000048/001, User Manual

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3 - 6 C
H A P T E R
3: T
R O U B L E S H O O T I N G
On-line Operation
Data is scrambled
Check t hat the character format (data bits, parity, and stop bits) is set to
the same value in both modems.
Missing data during a transfer
Check t hat you are using the same method of flow control for both the
modem and the DTE.
If using XON/XOFF flow control, check t hat the modem’s parity matches
the DTE’s parity.
Private-line Operation
Modems do not train-up on private lines
Check t hat the correct cabling is used for your application.
Check t hat one modem is configured for answer mode and the other is
configured for originate mode.
Check t hat both modems are using the same modulation scheme.
Dial Backup Operation
Modems do not establish a PSTN link when the Private line fails
Check t hat the communicating modems are configured to support dial
backup, as described in the AccessBuilder 7000 AT Command Reference .
Check t hat one modem is configured to initiate the backup (i.e. is the
master modem, and has the backup telephone number stored in its
directory location 8) and the other modem is configured to be a slave
(its directory location 8 is empty).
Check t hat both modems are using the same modulation scheme over
their PSTN line .