Re: (PM) Can't Get Network Dial-In Modem to

Jay Hennigan (jay@west.net)
Sun, 9 Nov 1997 00:15:05 -0800 (PST)

On Sat, 8 Nov 1997, qcislands net SCO Unix/Win95 site wrote:

[somebody else wrote...]

> >Not any sportster I've seen.
>
> >&Dn n=0 Ignore DTR
> > n=1 On-Line Command Mode
> > n=2 DTE Controls DTR
>
> I suppose my Sportster User's Guide (C) 1996, Part III: Section D: Technical
> was mis-printed. It *clearly* indicates:
> &D0 DTR override
> &D1 DTR toggle causes online Command mode
> &D2 Normal DTR operations
> &D3 Resets on receipt of DTR

Somewhat of a semantic difference in the case of the first three.

&D0 = ignore DTR = DTR override (the modem will over-ride what it sees on
DTR with a "true" state, thus ignoring the dTR signal).

&D1 = Dropping DTR puts the modem in command mode.

&D2 = Normal. DTR is controlled by DTE (the terminal server or computer).
And, NORMALly, dropping DTR will cause the modem to disconnect.
This is often used in "dumb" applications along with a DTR-controlled
dialer. Turning on the terminal brings DTR high, which causes the
modem to dial out. Turning the terminal off drops DTR, hanging up the
line.

&D3 may have been added later on in the code. It disconnects the line just
like &D2, but also resets the modem a la ATZ, forcing it to a sane
state with a known DTE speed.

For Portmaste applications, if your modem supports &D3, use it.
Otherwise use &D2.

-- Jay Hennigan jay@west.net --
WestNet: Internet service to Santa Barbara, Ventura and the world.
805-892-2133 805-289-1000 805-578-2121

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