System Administration Guide
Chapter 7, Connecting to other computers with UUCP

Alarms in UUCP audit output, data is not transferring

Alarms in UUCP audit output, data is not transferring

When sending data, UUCP expects a certain packet size and checksum on the packet. If it does not receive a full packet in a certain amount of time, a timeout occurs, which generates an alarm. A problem can sometimes occur once UUCP has begun sending data, in that part way through the transfer, alarms are generated and UUCP attempts to resend the packets. There are a couple of possible reasons for this problem.

First, check that mapchan(M) is not being used on the line that uucico is using. If it is, enter:

mapchan -n ttyxx

to turn mapping off for that port. If mapchan is not running on that port, there is probably some kind of line noise or modem problem that is corrupting the data being sent.

Alternatively, the problem may occur if you are using UUCP with MNP 5 or some other error checking protocol that is specific to the modems. Error checking on a modem also sends a certain packet size with a checksum. The problem is that the sending modem waits to get a certain amount of data before it sends the packet, which can cause problems with UUCP because it is also waiting for a packet. The solution is to not use error checking on the modem when using UUCP (UUCP has its own error checking).