IBM 701C Modem Init Notes

[owen@world.std.com (Rod Owen)]

Thanks to good help from the staff at The World (world.std.com),
I'm having good luck connecting to their local modems and staying online.

Here's what I've found, and I'd like to solicit your comments on it:

1.  Emmanuel's suggested init string (at&f1&c1&d2&k3&q5s95=41):  The
	&c1, &d2 are default settings for either the &f or &f1 factory
	settings, anyway, as can be seen by using at&v to view them.
	The &k3 is bolded in the manual to show that it's also a default
	(bidirectional hardware flow control), but it doesn't show up
	in the at&v display  of settings, however \q3 does show up
	and has the same meaning.  Note also that the &q5 sets MNP
	autoreliable mode, but that's also what the &f1 does.  Finally,
	the s95=41 must be a throwback to some earlier modem of his.

	Therefore, Emmanuel's string can just as well be at&f1, and
	that will get you MNP autoreliable mode, but it doesn't solve
	the problem -- or didn't for me.

2.  I haven't verified the manual's claim that "commands you enter must
	be entirely in uppercase or entirely in lowercase. A command such
	as At&f will not be recognized by the modem" (page 5), but
	maybe I've had problems there without realizing it.

3.  Someone recently posted a reply to the 701C modem-problem thread to the
	effect that the 701C's modem supports 19200 bps data mode, but
	only with other V.32 Terbo modems.  This finally made sense to me
	in working with the staff at World today, and I think it's the
	answer to _my_ connect problems.

	World's modems are all the same brands, and I could connect and stay
	on if I called their Brookline modems, but not their Lowell ones,
	I think because the Lowell ones were influenced more by peak
	usage demands.  Maybe.  I could also connect to CompuServe and
	to the Microsoft Network without getting thrown off.  (However,
	downloading from CompuServe and perhaps downloading in general is
	perhaps a different issue.)

	The diagnosis:  user greed.  The answer:  use %b14400 to limit
	the speed at which your modem will talk to someone else's.  I
	know that all those connect at 19200 messages are gratifying
	to see, but either the other guy's modem has trouble maintaining
	the connection, or my modem has trouble.

	My init string is now at&f%b14400w1.

	I use the w1 to tell me what connection details result from the
	modem's negotiations.

4.  I've only had luck setting my port speed to 19200.  The manual says
	"a speed of 19.2Kbps will almost always work with any computer"
	(page 39).

5.  Someone asked, "When the modem says 'Connect 38400/REL, is it kidding?"
	What's really happening is that this is the speed at which your
	serial port is willing to talk to your modem.  It's not the
	speed at which your modem will talk to another modem.  This
	is a little more clear when you use the w1 command, as in this
	capture of my connection:

	atdt 9349753
	CARRIER 14400			/* max per %b14400 command */
	PROTOCOL: LAP-M			/* result of &f command */
	COMPRESSION: V.42BIS		/* ditto */
	CONNECT 19200			/* my port speed */

	If I didn't have the w1 command, I think all I would see
	would be "CONNECT 19200/REL."

6. Following the suggestions from Tech Support at IBM, I updated my
	system's BIOS to version 3O by using the sys7013o.exe file
	that you can find on CompuServe or http://www.pc.ibm.com/files.html.

	I don't think that it made a difference, and it's kind of scary.
	You need to download it, run sys7013o to unpack it and put it
	onto a blank, formatted diskette, read the directions, boot
	the 701 from the diskette, and, in my case, hold your breath
	when the screen goes blank and you (I) turn the 701 off and on
	before you see the message telling you to do so.  (It must be a
	bug in the program, or maybe the 5 minutes I waited wasn't long
	enough.)

7.  I also updated my modem's BIOS with the file bfmod611.exe, which has
	a basically similar procedure to updating the system BIOS, and I
	went from Rev A6.09 to Rev A6.11a for my firmware.

	Again, I wouldn't recommend that you do this, as I'm not sure it
	made any difference.  This file isn't in their general customer
	area anyway.

Well, that's it.  The last three (!) times I've connected to World, I've
been able to stay on as long as I've wanted.  This is quite a change from
the two-to-five-minute connection I've had since the machine arrived two
weeks ago.

Now, if anyone has suggestions for avoiding the "death spiral" when down
loading from CompuServe, where the speed goes from 2000 bps down to 250
or so before hanging, I'd really like to know.  I don't know if I'll
have problems with that now after what I've learned so far.  But you
never know.  I also don't know if my suggestions will produce a reliable
Netscape session.

If these suggestions work for you, will you please let me know?

Thank you.

- Rod Owen
	Rod@acm.org
	Owen@world.std.com