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Path: utzoo!watmath!watnot!watcgl!onfcanim!dave
From: dave@onfcanim.UUCP (Dave Martindale)
Newsgroups: net.bugs.uucp
Subject: Re: Modem doesn't hang up provokes misdirected flame
Message-ID: <14768@onfcanim.UUCP>
Date: Sun, 29-Dec-85 23:16:42 EST
Article-I.D.: onfcanim.14768
Posted: Sun Dec 29 23:16:42 1985
Date-Received: Mon, 30-Dec-85 04:53:30 EST
References: <115@sat-bc.UUCP> <478@uwvax.UUCP> <5821@fortune.UUCP> <364@l5.uucp>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: ONF, Montreal
Lines: 49

In article <364@l5.uucp> gnu@l5.uucp (John Gilmore) writes:
>
>Maybe the real moral is that if you buy "affordable" system software,
>buy two modems.
> [discussion of how a modified tty driver can talk to a modem
> even though Carrier Detect is still low]
>Don't complain about the modems -- they work.  Fix your software.
>I'll repost the driver fix if enough people haven't seen it.

Indeed, this mechanism works well for supporting dialout.  However, it
is still worth looking carefully at the features of various modems,
with an eye to how you are going to use them.

One difference is in how "chatty" a modem is, and under what
circumstances.  The ideal behaviour is for them to be perfectly silent,
just like a dumb modem, when someone is calling in so getty doesn't get
"CONNECTED" or some other announcement and try to use it as a login
name.  But for dialout, you want the modem to talk back, telling you
that the call succeeded or failed.

Hayes Smartmodems are a pain to use for dialin and dialout, since there
is only one switch that selects whether they are silent or chatty.  If
you want to use it for dialin, you make the modem silent, but then you
get no information when you are making a call.

My other modem experience has been with the VADIC 3450 series, and they
do just what you want - silent answering but verbose calling.

Also, if you want to give people the same modems to use at home as you
put on your computer, you may want them to remember a few phone numbers
so they can be called without typing the number every time.  Many modems
with autodialers have this, but the Hayes loses again here.  (In my mind,
this makes naming the Hayes modem a "smartmodem" rather laughable).

If you do a lot of long-distance dialing, you may want tone dialing; some
modems are pulse-dial only.  Also, some computers can be reached only by
tone dialing, since you have to dial a regular phone number and then dial an
access code to a PBX at the far end.

Some modems adapt to tone or pulse dialing automatically by sending the
first digit as a tone and seeing if it breaks dial tone.  If it doesn't,
they redial the number from the beginning using pulse.  Some telephone
exchanges do not break the dial tone after the first digit, or give you
a second dial tone (particularly if the digit is "9" to get an outside line).
You can't use one of these modems with one of these telephone lines.
Better to have a modem where you can explicitly tell it which parts of
a number are to be tone and pulse, with no guessing on the modem's part.

	Dave Martindale