AT Command Reference: Erratum (4/97)

I have a copy of the AT Command Reference, which I downloaded from one of Apple's Software Update locations. I need to slow my GeoPort modem to 14.4 Kbps. I am confused by the presentation for the S110 register on page 17, which states the following:

S110 Modulation Selector
------------------------
0 V32/V32bis enabled, V34/34 (33.6) disabled
1 V32/V32bis enabled, V34/34 (33.6) disabled
2 Full modulation set available
7 V34 (33.6) only enabled

The descriptions for the first two settings seem identical. Should they be?

There is an error in the documentation.  The first two items should read:

0 V32 enabled, V32bis disabled, V34/34 (33.6) disabled
1 V32/V32bis enabled, V34/34 (33.6) disabled

To elaborate:

V32 = 9600 baud protocols
V32bis = 14.4 Kbps protocols
V.34 = 28.8 Kbps protocols.  Recently, this standard was upgraded to include 33.6 Kbps protocols; Apple Telecom software version 3.1 or newer will support these protocols on Power Macintosh computers.

As an example, passing the command ATS110=0 to the modem will turn on 9600 baud only.

Passing the command ATS110=1 will allow the modem to adjust speed to 9600 or 14.4 Kbps as necessary, and will turn off 28.8 or 33.6 Kbps performance.

These articles can help you locate the AT Command Reference document mentioned in this article:

"Where To Find Apple Software Updates" - Lists online services for free Apple software updates.

"Obtaining Apple Product Support in the USA" - Lists 800 numbers and online services for software updates, Apple support information, and a subset of the Apple Tech Info Library.


This article was published in the 21 March 1997 "Information Alley."


Article Change History:
01 Apr 1997 - Made correction for technical accuracy.
21 Mar 1997 - Added Information Alley statement.

Published Date: Feb 18, 2012