This is - Helping you get the best performance from your modem
 Troubleshooting News Technical Search
 Home Forum 56 Premium Site Map
Home Troubleshooting    LT Win Modem    About the LT / 33.6k 
About the LT 33.6k/AT&T Trouble with the LT  NT, 2k & Linux Compaaq & LT
What Driver Where to find Driver Upgrade Procedure AT Commands Handshake/Diags

About the Lucent/Agere "LT Win Modem":

Agere, formerly Lucent,  doesn't make the modems - they make the chipset and develop the driver.

A number of major computer manufacturers, including IBM, HP, Dell, Gateway and Compaq put the LT modem in some of their computer models. Modems based upon this Lucent chipset are also sold at retail under various brand names, and sometimes without a brand name.

The LT is a "controllerless" modem - which has some advantages. One advantage is the ease of updating the modem's firmware - the modem does not need to be flashed. (With other modems, if there's a glitch in the flash procedure, you wind up with a paperweight.) Believe it or not - I think this inexpensive Win Modem is one of the best 56k modems available today! A major factor with 56k is the firmware: the LT has no equal in availability of various, frequent, firmware improvements - no modem has more 56k versions than the LT! (The firmware - programming for the modem's DSP - is contained in the driver.) Note: this modem will not work on unsupported operating systems. Currently it is supported only on Intel x86-compatible systems with Windows9x,Me,NT,2K and XP; OS/2 on the IBM Thinkpad; and Linux. (There shouldn't be a problem with using an "x-86-compatible" AMD processor.)

Drivers for the modem from almost any source (see Driver section) can be used with any other vendor's LT Win Modem. (Note - Lucent has produced "generic" upgrade releases designed to setup and upgrade all LT-based modems. OEMs may include a subset, or make modifications to the firmware/driver package that may not work properly, or support all features, with other vendor's LT modems.  Notebook computers with cellular port can use other driver but you may lose support for the cellular connector; you may also have to update the .inf file or init string to prevent the cellular port init command )C2 from being sent to the modem.)

AKAs: The LT Win Modem is also known as "Apollo" or "Mars". (Lucent uses Apollo to refer to the ISA-bus version and Mars for the PCI-bus version.) Various OEMs may use various names or model numbers to identify LT-based modems. DSP Chip numbers include Lucent or Agere 1641, 1643, 1644, 1645, 1646, 1648, 1648C. The latest DSP, Mars 3.2, is 1648C. (The 1646 may also have been labeled HV90 on some modems.) The 1648C DSP works with a solid-state DAA (on/off hook circuit) as does the 1643. The easiest way to tell which DSP your modem uses is to look at the modem card itself. V.92 LT Modems based upon the 1646 DSP will not have any V.92 functionality with driver versions later than 8.12. Only modems with the 1648C DSP will provide V.92 with drivers later than 8.12. How to tell which DSP you have: the surest way is to power down, remove the modem from your system, and look at the numbers of the largest chip on the modem card. (See this picture of a 3025L.)

DATA/FAX/VOICE - A manufacturer can make a modem using the Agere/Lucent chipset that supports data and fax, or data, fax and voice. All LT modems support the full data/fax/voice command set; but, if the modem doesn't have voice capabilities, the modem will respond with 'OK' to voice commands even though there is no voice support.

CHIPSET: A single common driver is used for modems in this family which can be made from a number of different chip combinations. The DSP (digital signal processor) may be one of the following chips numbers: 1641B, 1641C, 1643, 1644, 1645, 1646, 1648 or HV90. 

Distinctive Ring: The LT modem uses the V.253 standard DRON/DROFF method for distinctive ring support; however, Microsoft operating systems do not support this standard, so MS-Windows programs (like MS Fax) may not recognize distincitve ring. See: MS KB Distinctive Ring Troubleshooting Win9x; MS KB Distinctive Ring with Windows 2000 Fax.

What if I have an AT&T/Lucent WinModem 33.6k?

Before 56KFlex was finalized, AT&T/Lucent made a 56k-capable 33.6k version of the LT Win Modem. In many cases, all that is needed to upgrade the modem to 56k is a 5.xx driver installation. In some cases (notably Compaq-supplied 33.6k modems), a hardware upgrade of the modem card as well as the driver installation is required. In all cases, the new driver version will work with the AT&T/Lucent 33.6k modem, but if a hardware upgrade is required, 56k connects will not be attempted (see handshake). Upgrade by running modem5##.exe. The existing modem will be removed, and the modem will be re-installed with a new name (LT Win Modem or Lucent Win Modem depending upon the driver version.) You will need to change your dial-up networking connection(s) to use the 'new' modem.

Also see: Agere Modem Chipsets 

Home  |  Links  |  Send Feedback  |  Privacy Policy  | Report Broken Link
Legal Page  |  Author's Web Sites   |  Log In 1998-2022 v.Richard Gamberg. All rights reserved.