Are we talking about a timeout for delivery of unsolicited result
codes?  Three minutes is a very long time for any other
interpretation of "command time-out".  Do you mean something
else?

The only immediate sense I can make of the notion is that perhaps
the unsolicited result codes will be buffered for a certain
maximum time if the interface is in data transfer mode, and not
in command mode.

If this is your concern, and you want to read those codes while
you've got a data circuit going, you could periodically escape to
command mode using the "+++" mechanism before returning to data
transfer mode with "ATO".

But this interpretation of your question doesn't fit well with
your asking about "faster modules".

John