US Robotics Courier V.Everything x2 Addendum User manual

Courier™V.Everything™
Command Reference Addendum
Macintosh Modems
Congratulations! You have just purchased a U.S. Robotics Courier
V.Everything that is x2-capable. x2 is a groundbreaking new technology
that allows your modem to use normal analog phone lines to connect at
speeds up to 56 kbps.
Information about x2
For more information about x2, visit the U.S. Robotics x2 Web Site
at http://www.usr.com/x2

2
The material contained in this document is for information purposes only and is
subject to change without notice. U.S. Robotics makes no representations or
warranties with respect to the contents hereof and specifically disclaims any
implied warranties of merchantability or fitness for any particular purpose.
No part of this document may be reproduced, transmitted, transcribed, or stored
in a retrieval system in any form or by any means, mechanical, magnetic,
electronic, optical, chemical or otherwise, without the written permission of
U.S. Robotics.
U.S. Robotics and the U.S. Robotics logo are registered trademarks of U.S.
Robotics Access Corp. Any trademarks, tradenames, service marks or service
names owned or registered by any other company and used in this manual are
the property of their respective companies.
U.S. Robotics assumes no responsibility for errors or omissions in this manual.
Nor does U.S. Robotics make any commitment to update the information
contained herein.
1996-1997 U.S. Robotics
8100 N. McCormick Blvd.
Skokie, IL 60076-2999 USA

Contents
Contacting U.S. Robotics 1
Enhanced x2 Features 1
How to Tell if x2 is Enabled in Your Modem 2
How x2 Works 3
The Shift from Analog to Digital Circuits 3
Client and Server Modems 3
Client Modems 4
Server Modems 4
Making x2 Work 4
A Digital Connection At One End 4
Only One Digital-to-Analog Conversion 4
Controlling x2 5
Controlling Link Speeds with &N and &U 6
Controlling Link Speeds 6
Limiting the Highest Possible Connect Speed 6
Limiting the Lowest Possible Connect Speed 6
Limiting a Range of Possible Connect Speeds 7
&N and &U Command Values 8
Configuring the High Speed (HS) LED 9
Troubleshooting x2 Client Connections 10
New x2 Result Codes 11

Courier V.Everything x2 Addendum1
Contacting U.S. Robotics
We’ve made every effort to provide you with useful, accurate information. If
you have any comments or questions, please let us know.
To do this
Contact
Contact U.S. Robotics Technical Support
800.550.7800
Visit the x2 web site
http://www.usr.com/x2
Enhanced x2 Features
Your Courier I-modem with x2 has new result codes and the following new
features. Refer to later sections of this Addendum for more information.
To do this
Use this command
Detemine if x2 is enabled in your modem
ATI7
Disable or enable x2
ATS58
Limit the upper speed limit of an x2 connection
AT&N
Limit the lower speed limit of an x2 connection
AT&U
Configure the High Speed (HS) LED
ATS69
Note: New x2 features should be transparent to most users. If you are an
advanced user, see ”Controlling x2” and “Controlling Link Speeds with &N
and &U” for detailed information regarding these new features.

2
How to Tell if x2 is Enabled in Your Modem
If you aren’t sure whether x2 is enabled in your Courier modem, use theATI7
command to display product configuration information. If x2 is enabled on
your Courier modem, the following information displays:
USRobotics Courier I-modem Configuration Profile...
Copyright, 19xx-96, U.S. Robotics. All rights reserved.
Product type US/Canada External
Options HST,V32bis,Terbo,VFC,V34+,x2
Fax Options Class 1,Class 2.0
Clock Freq 20.16Mhz
Eprom 256k
Ram 32k
Supervisor date 02/01/97
DSP date 02/01/97
Supervisor rev 7.0.0
DSP rev 2.0.0
Serial Number {serial number}
OK
Note: Dates, serial numbers, and revision numbers may vary. The most
important line is the “Options” line, which lists support for x2.

Courier V.Everything x2 Addendum3
How x2 Works
U.S. Robotics' x2 technology enables analog modems to receive data at up to 56
kbps over the standard analog, public switched telephone network (PSTN). x2
overcomes the limitations imposed on standard, analog modems by exploiting
the digital connections that most Internet and online service providers have at
their end to connect to the PSTN.
The Shift from Analog to Digital Circuits
When the first telephone networks were established, they were completely
analog. Over time, telephone companies began replacing portions of their
analog networks with digital circuits, which provided a higher telephone signal
quality at a more economical price.
Today, the PSTN is almost entirely digital. Typically, the only portion of the
telephone network that remains analog is the line that connects your home to
the telephone company's central office (CO). The rest of the telephone network
is digital.
Client and Server Modems
x2 will not require changes to your wiring and equipment that's already in
place. All that's required to use x2 is a software upgrade.

4
Client Modems
x2 client modems can receive data at speeds up to 56 kbps and send data at
V.34 speeds. The following products are examples of U.S. Robotics Client
Modems:
• Courier™ V.Everything™ with x2
• Sportster® with x2
• Analog Modem Pools or NETServer with x2
Server Modems
The digital x2 modems that client x2 modems connect to are called server x2
modems. Server modems can send data to client x2 modems at speeds up to 56
kbps. A server must have a “digital” interface to the PSTN. This digital
interface can be in the form of a “trunk-side” T1, Primary Rate Interface (PRI) ,
or Basic Rate Interface (BRI). The following products are examples of client x2
modems:
• Courier I-modem with x2 (in Server Mode)
• Quad Modem 5.0/5.1 (in Server Mode)
• MP I-modem or NETServer I-modem with x2
Making x2 Work
To use x2, the client x2 modem must connect to a server x2 modem. If clients
attempt to connect to ISPs that do not use x2, the client modem will negotiate
the next available modulation. For example, an x2 client modem calling into an
ISP that only supports V.34, the modem will only negotiate the highest v.34
connection rate. The maximum V.34 connection speed is 33.6 kbps.
When a client x2 modem connects to a server x2 modem, the path through the
telephone network between the modems is subject to the following conditions
for an x2 connection to be made.
A Digital Connection At One End
ISPs or online services must have a digital connection to the PSTN. Most major
online services have digital connections to the PSTN.
Only One Digital-to-Analog Conversion
There can be only one digital-to-analog conversion in the telephone network
between the x2 server modem and the x2 client modem.

Courier V.Everything x2 Addendum5
Controlling x2
Use the following S58 settings to control x2:
To do this
Use this command
Disable x2
S58.0=1
Force A-law mode
S58.2=1
Table 1- S58 Settings
Note: A-law is required in all countries but the United States, Canada, Japan,
Taiwan, and Hong Kong. If you are using your Courier in one of these
countries, do not force A-law mode.

6
Controlling Link Speeds with &N and &U
You can use the &N and &U commands to control link speeds. Couriers
without x2 can still use the &N and &U commands, but can only control link
speeds up to 33.6 kbps.
Controlling Link Speeds
You can use the &N and &U commands to control the link speeds of your
Courier I-modem with x2. Use the following table to determine how to use &N
and &U commands:
To limit the
Use
Highest possible connect speed
&N
Lowest possible connect speed
&U
Range of possible connect speeds
&N and &U
Table 2- Using Link Speeds
Note: The default values for &N and &U are 0. If you change these values, you will
limit the speeds at which you can connect. U.S. Robotics recommends that you do not
alter these values.
Limiting the Highest Possible Connect Speed
The &N command allows you to limit the highest possible connect speed. If a
remote modem connects to your Courier I-modem with x2 at a speed higher
than &N, your Courier I-modem with x2 will not allow it to connect.
To limit the
Use this command
Highest possible connect speed to 33600
&N=16
Limiting the Lowest Possible Connect Speed
The &U command allows you to limit the lowest possible connect speed. If a
remote modem connects to your Courier I-modem with x2 at a speed lower than
&U, your Courier I-modem with x2 will not allow it to connect.
To limit the
Use this command
Lowest possible connect speed to 48000
&U=24

Courier V.Everything x2 Addendum7
Limiting a Range of Possible Connect Speeds
By setting &N and &U values, you can limit the range of speeds at which your
Courier I-modem with x2 connects. If a remote modem does not connect to
your Courier I-modem with x2 at a range between the speeds designated by the
&N and &U commands, your Courier modem with x2 will not allow it to
connect.
Note: The link speed associated with the &U argument cannot be greater than
the link speed associated with &N argument.
Use the following table to understand the relationship between &U and &N
commands:
If &U
And &N
Then your modem
Equals zero
Equals zero
Connects at the highest possible speed.
Is greater than zero
Connects at the &N speed only.
Is greater
than zero
Is greater than zero
and greater than &U
Connects at the highest possible speed
in the range from &U to &N.
Table 3- Constraints on Link Speed

8
&N and &U Command Values
Use the following table for a complete list of &N and &U link speeds and their
associated indexes:
Link
Speed Index Link Speed Index Link Speed Index
Highest 0 21600 11 45333 22
300 1 24000 12 46666 23
1200 2 26400 13 48000 24
2400 3 28800 14 49333 25
4800 4 31200 15 50666 26
7200 5 33600 16 52000 27
9600 6 33333 17 53333 28
12000 7 37333 18 54666 29
14400 8 41333 19 56000 30
16800 9 42666 20 57333 31
19200 10 44000 21 64000 32
Table 4- Link Speeds and Indexes
Note: For x2-mode links, &N and &U are used to constrain the speed of the
higher speed direction of the link.

Courier V.Everything x2 Addendum9
Configuring the High Speed (HS) LED
You can configure your Courier to alert you when it reaches x2 speeds. Use the
following S69 setting to configure the HS (High Speed) LED:
To do this
Use this command
Configure the HS (High Speed) LED to turn red
when your modem reaches speeds over 33.3 kbps.
S69=12

10
Troubleshooting x2 Client Connections
Use the chart below to understand issues affecting your Courier modem and
how to fix them:
Step
This may be the issue
Do this
1
x2 may not be enabled
on your Courier.
See the section
“
How to Tell if x2 is
Enabled
”
(Use the
ATI7
command)
2
Several conditions
may exist.
Use the ATI11 command and check the
“
x2
status
”
field for more information.
If this message
appears
You cannot use x2
because
“
Multiple
CODECS in
channel
”
There are multiple
analog-to-digital
conversions on the
channel.
“
Remote modem
is not x2
”
The remote modem
does not support x2.
“
Channel is x2-
capable but
feature is not
installed
”
You have not
purchased x2.
3
Your Courier may be
connected to the
public network via a
PBX or other
telephone equipment
with analog-to-digital
and digital-to-analog
conversions.
Contact your telephone equipment vendor
for information about obtaining pure
analog service.
Due to extra analog-to-digital conversions
performed by some PBX’s and other
telephone equipment, x2 client modems
may not be able to make x2 connections.
4
There is another issue.
Do the following:
•
Visit the U.S. Robotics x2 Web Site at
http://www.usr.com/x2
•
Contact U.S. Robotics Technical
Support at 800.550.7800

Courier V.Everything x2 Addendum11
New x2 Result Codes
Use the following table for a list of all result codes, including new x2 result
codes:
Numeric Alphanumeric
180 CONNECT 33333
181 CONNECT 33333/ARQ
182 CONNECT 33333/x2
183 CONNECT 33333/ARQ/x2
184 CONNECT 37333
185 CONNECT 37333/ARQ
186
CONNECT 37333/x2
187 CONNECT 37333/ARQ/x2
188 CONNECT 41333
189 CONNECT 41333/ARQ
190 CONNECT 41333/x2
191 CONNECT 41333/ARQ/x2
192 CONNECT 42666
193 CONNECT 42666/ARQ
194 CONNECT 42666/x2
195 CONNECT 42666/ARQ/x2
196
CONNECT 44000
197 CONNECT 44000/ARQ
198 CONNECT 44000/x2
199 CONNECT 44000/ARQ/x2
200 CONNECT 45333
201 CONNECT 45333/ARQ
202 CONNECT 45333/x2
203 CONNECT 45333/ARQ/x2
204 CONNECT 46666
205 CONNECT 46666/ARQ

12
New x2 Result Codes (Continued)
Numeric Alphanumeric
206
CONNECT 46666/x2
207 CONNECT 46666/ARQ/x2
208 CONNECT 48000
209 CONNECT 48000/ARQ
210 CONNECT 48000/x2
211 CONNECT 48000/ARQ/x2
212 CONNECT 49333
213 CONNECT 49333/ARQ
214 CONNECT 49333/x2
215 CONNECT 49333/ARQ/x2
216
CONNECT 50666
217 CONNECT 50666/ARQ
218 CONNECT 50666/x2
219 CONNECT 50666/ARQ/x2
220 CONNECT 52000
221 CONNECT 52000/ARQ
222 CONNECT 52000/x2
223 CONNECT 52000/ARQ/x2
224 CONNECT 53333
225 CONNECT 53333/ARQ
226
CONNECT 53333/x2
227 CONNECT 53333/ARQ/x2
228 CONNECT 54666
229 CONNECT 54666/ARQ
230 CONNECT 54666/x2
231 CONNECT 54666/ARQ/x2
232 CONNECT 56000

Courier V.Everything x2 Addendum13
New x2 Result Codes (Continued)
Numeric Alphanumeric
233 CONNECT 56000/ARQ
234 CONNECT 56000/x2
235 CONNECT 56000/ARQ/x2
236
CONNECT 57333
237 CONNECT 57333/ARQ
238 CONNECT 57333/x2
239 CONNECT 57333/ARQ/x2
240 CONNECT 64000
241 CONNECT 64000/ARQ
242 CONNECT 64000/x2
243 CONNECT 64000/ARQ/x2
Table 5- New Result Codes
There is a complete list of result codes in your CourierCommand Reference.
This PDF file is based on print document 1.024.1096-00