jacob@gore.com (Jacob Gore) (04/13/90)
NextAnswers/April_90/sysadmin.440 ("NeXT Serial Port Connectivity") says on
Page 8:
Note: If you are using a Telebit modem and you expect incoming
calls from V.32 or "low-speed" (that is, non-PEP) modems, always
connect out at the same speed at which you told getty to expect an
incoming connection. Other modems usually won't connect at over
9600, so you may want to step getty down to std.9600. The whole
problem stems from the fact that the Telebit cannot have different
speeds from modem-to-modem and modem-to-cube in low-speed or V.32
mode (see page 5-41 of the Telebit T2500 Reference Manual).
But the referenced passage from the Telebit manual says:
When the connection is made in V.32 or Low Speed mode AND FLOW
CONTROL IS NOT ENABLED [emph. added -J] (S66=0 or S66=2 and a
non-MNP connection is established), the local DTE [that's the cube
-J] must be set to match the modem's transmission speed indicated
by the CONNECT XXXX result code.
I don't see what the problem is. If you use neither flow control nor an
error-correcting protocol (PEP or MNP), the modem may lose data when the
speeds on both sides of it don't match.
So what's the big deal? What keeps one from enabling XON/XOFF flow control
and leaving the interface speed locked at 19200?
Jacob
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Jacob Gore Jacob@Gore.Com boulder!gore!jacob