[net.dcom] Modem diagnostics mode

mark@cbosgd.UUCP (Mark Horton) (02/29/84)

I'm sure many of you know about the "feature" of modems where due
to line noise, one modem suddenly prints U's and goes into test
mode.  This mode can be disabled by flipping a switch, but seems
to be enabled by default.

My question is: is there any way to tell which of the two modems
is the one that needs the switch disabled other than tearing them
open?  (It's often hard to do when rotaries are involved.)  If I
see a bunch of U's and then everything I type is just echoed
(and I can see SD and RD flash on each character), can I assume
it's the remote modem that has the problem?

	Mark