John, at 20:31 on Dec 02 1996, you wrote to All ...

JP> Last week, and just five minutes ago, I discovered that my 
JP> Courier would not answer any inbound calls. Several tests 
JP> with my other line and mobile proved that there was a 
JP> definite problem. The auto-answer LED on my Courier's panel 
JP> would flash while the line was ringing, but my mailer would 
JP> fail to show any signs of a RING signal. Jumping into 
JP> terminal mode, I dialled my line again. ASCII garbage of 
JP> equal amounts would echo to the screen in place of a RING.

JP> In both cases, I found that rewriting the modem's profile 
JP> (AT&F1&K3) did the trick and fixed the problem; the Courier 
JP> would once again recognise RING and answer the call. I have 
JP> no idea why this suddenly started happening.

JP> Anyone have any explanation for this odd behaviour? Could it 
JP> be a fault with NVRAM? I'd be interested in hearing people's 
JP> thoughts on the matter. I don't particularly want to rewrite 
JP> my modem's profile regularly.

Do you run your modem init string in your BBS/mailer software as ATZ perchance?

When you ATZ a USR it immediately switches the port speed to what it was
set to last time it was AT&Wed.

If you write your settings at 38,400, and then run your mailer at 57,600,
the first ATZ sent out by the mailer switches the modem's port to 38,400. 
Your software is listening at 57,600 and your modem is sending RING at
38,400

This anomoly is mentioned in the documentation (but not very loudly).  A
trap for new(ish) USR owners :-)

David
@EOT:

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