SocketModem question

Interesting problem.

Maybe a dumb question, but... are you sure you have hardware flow control turned on in the modem? Does it work otherwise? (See AT&K3)

Also, a reference in the docs states that RTS/CTS is only supported when the SocketModem DCE interface is slower than the modem line rate.

Thanks for the reply. I'm sure the flow control is active as I've accesses S39 to check. The SocketModem uses a Conexant chip and since my original message I've tracked down a datasheet of a similar chip which mentions something about RTS not being used in command mode. I suspect this is the simple answer. I would be interested to know the reference that you refer to in your reply though as I've found the documentation on the SocketModem to be fairly poor.

Thanks,

Roger.

What's the oscillator on the M128? I have seen problems with using the internal oscillator because, although it may be nominally 8MHz - say, the frequency is not quite right so your baud rate is wrong. Some devices can be alot more sensitive to slight baud rate errors than others.

Iain

Section 2.3 re: Flow Control. Re-reading it, my interpretation was backwards - it supports signalling toward the DTE when the line rate is slower than the port speed. That makes more sense.

I can see some logic in having command responses bypass the flow control, since they are typically very small replies and it'd let you pause the normal data stream and still manipulate the modem. Still, you'd think this would be worth a mention in the docs.

Yes, my understanding is HW flow control would only be enabled for data mode.

You might consider putting the modem into "short response mode" (ATV0). That way it only issues a single char response to most commands.

serial