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Modem Issues

How do I turn V.90 on and off?

Most V.90 Modems should default to the new V.90 standard.  Some however, require a few setting changes to obtain those connections.

The settings vary between Chipset brands.  The new settings must be added to a modem init string.  In Windows® 95, Windows® 98 and Windows NT® 4.0, you can do this by going into control panel, modems, properties (of your modem), connection, and then advanced.  Simply add it to the extra settings field.

Follow these steps to improve your connection (only try these if you are having a problem.)

1. Turn off flow control. 
2. Force V.90 through the modem AT commands. 
3. Try adding 2 to 5 commas after the dial string. 

A list of specific modem speeds to limit to can be found at http://808hi.com/56k/x2-linklimit.htm

Manufacturer specific AT commands

• Lucent Chipsets
• Rockwell/Conexant Chipsets
• X2 Chipsets
• PCTEL Chipsets
• Motorola
• Gateway Telepath 56K

Lucent Chipset Modems (www.lucent.com)

For Apollo (LT Win Modem) and Mars (LT PCI Win Modem) chipsets:

For Venus chipsets (mostly found in external modems):

* Which protocol will be used? Assuming that the ISP supports both, it depends on the firmware. Some versions will prefer K56flex, others will prefer V.90.

• For LT Win Modems having slow speeds and disconnection problems when dialing in to a PortMaster running Lucent ComOS ® 3.8 or later, try entering -v90=1 to enable V.90 on the modem. 
• You may need to have the modem ignore the V.8 tone, by adding 2 to 4 commas after the dial string. 
• For LT Win Modem driver updates, see the manufacturers website (such as the computer manufacturer if it came with your computer),  http://www.808hi.com/56k/x2-lucent.htm#firmware or http://56k.com/reports/ltfaq.shtml. 
• For technical support for Lucent LT Win Modem, call the company that made the modem (such as computer manufacturer if it came with your computer) or 1-800-372-2447. 

Rockwell/Conexant Chipset Modems (www.conexant.com)

For most Rockwell chips including Dual:

* Remember that most Rockwell-based K56flex modem upgraded to V.90 no longer supports K56flex.

For Rockwell HCF & Soft56 chips:

** Rockwell HCF-based modems have difficulty connecting reliably past 41.3Kbps.  If you experience problems with your connections try the limit v.90 and disable v.90 commands.

COMPAQ HCF 
Compaq has a fix for the connectivity problem of the HCF Rockwell modems in their Presario computers. Some line impairments at the local telephone company loop levels might limit connections to V.34, but the connections stay up. See http://www.compaq.com/athome/support/softpaq/sp_desk.html for both modem driver and ROM updates. Call Compaq if you do not see your model listed. 

X2 Chipset Modems  (www.3com.com)

Note that these are different in some cases from the commands for x2-only modems.

* Using AT&F1 in the init string automatically enables both protocols.

**Non-U.S. Robotics modems that support x2 generally use the same commands as the Sportster with the exception of the Cirrus Logic and ESS modems.

For more specific commands, look at the U.S. Robotics Technical Reference.

PCTEL Chipset Modems  (www.pctel.com)

PCTEL based modems have a setting to disable auto sensing of 56k or V.34 modes.

ATN0 disables this setting.  ATN1 enables it.

* A typical init string is AT&F&C1&D1&K3W1

For custom command with the PCTEL chipset, visit http://users.penn.com/~asgard/aztech.html

Motorola Chipset (www.mot.com)

V.92 Connection INIT strings

HSP 56K MicroModem - N0S37=12

US Robotics V92 Winfax - AT&F&H3&R2&I2S7=90\

US Robotics 56k External (Verified on 5686D model) - s32=34 +PIG=1 +PMH=1 +PQC=3

US Robotics 56k External (Verified on 5699b model) - AT+PIG=1+PMH=1+PQC=3

Gateway telepath - AT&F&D0S15=128S32=34