Lucent LT Win Modem FAQ
This is one excellent feature of the LT Win Modems. No matter who sold you your modem - Compaq, CPI, Hewlett-Packard, IBM, Sony, etc. - the firmware is all the same. You can use any other company's firmware with one catch.
The only catch is that with older firmware there were separate versions for the LT Win Modem and LT PCI Win Modem. Beginning with firmware version 5.04, the LT Win Modem and LT PCI Win Modem use the same firmware, so everything is completely interchangeable (as per conversation with Lucent).
Incidentally, this does not work with most other modems. For instance, Rockwell chipset modems start out the same, but individual vendors (Hayes, Motorola, etc.) customize the chips and firmware before selling the modems. That's why there are no generic firmware upgrades for Rockwell chipset modems. Likewise for Cirrus Logic or U.S. Robotics chipset modems.
The other advantage of LT Win Modems is that installing new firmware can't possibly damage the modem. In contrast, with most modems there is a slight chance that upgrading the firmware will damage the programmable ROM chips.
Here are a few sources of LT Win Modem firmware and drivers. If you are experiencing problems or slow connects, it's always a good idea to get the most recent firmware.
56K.COM V.90 Upgrades - you can try finding upgrades from your manufacturer first. Your manufacturer may not have the latest version, though.
updated October 23, 1999
Yes. Check the resources listed above and use any of the files marked for Windows NT. Digitan is one company with NT files, though they may or may not be the latest.
Yes and no. This is one of the disadvantages of software-based modems: to function, they require drivers specific to the operating system.
Some progress has been made on the Linux front. Richard C has an alpha version of a Linux driver. (Alpha means that it is very, very buggy.)
updated October 5, 1999
Some Toshiba and Compaq embedded modems are LT Win Modems, even though they don't identify themselves as such.
No. Both are software-based, but the AT commands and other information in the FAQ only apply to LT Win Modems.
As with any 56K modem, many things can prevent high speed connections. Check the extensive advice in the 56K Troubleshooting Guide for curing slow connects.
Lucent advised several possible solutions. Part of the rash of current problems may be with the current code (1.2.5) in 3Com/U.S. Robotics HiPer DSP modems, used by a number of ISPs. Recent Lucent firmware (including 5.25) include workarounds for that specific problem.
Of course there can be lots of reasons for disconnects with any type of modem. Try the advice in the Disconnect section of the 56K.COM Troubleshooting Guide.
One strategy for eliminating disconnects is to try limiting the maximum connect speed. See "How do I limit the maximum speed?" below.
Some do, some don't, depending on how the distributor configured them. Lucent writes:
If your modem's hardware supports Caller ID, use the V.253 standard command AT+VCID=n command, where
Encore has one at http://www.encore-usa.com/Drivers/hostat.pdf. Lucent has confirmed that the commands will work for both ISA- and PCI-based LT Win Modems.
These strings are for ISA card Lucent LT Win Modems and PCI card LT PCI Win Modems.
For enable and disable strings for Lucent Venus chipset modems, as well as non-Lucent modems, see the V.90 Upgrade FAQ.
These strings are for Lucent LT Win Modems and LT PCI Win Modems. For other modems, see the V.90 Upgrade FAQ.
If the ATI3 response shows firmware version 5 or higher, the modem supports V.90. If you're having problems getting a V.90 connection, try upgrading your firmware, try explicitly telling the modem to use V.90 or K56flex (using one of the init strings above), or try the other advice in the troubleshooting guide.
In a terminal program, type ATI11.
These are example results using recent firmware. If your results are formatted differently, try upgrading your firmware.
The line numbers have been added for clarity. Each line is explained below.
Description Status --------------- ------------ 1 Last Connection 56K 2 Initial Transmit Carrier Rate 28800 3 Initial Receive Carrier Rate 50000 4 Final Transmit Carrier Rate 28800 5 Final Receive Carrier Rate 50000 6 Protocol Negotiation Result LAPM 7 Data Compression Result V42bis 8 Estimated Noise Level 152 9 Receive Signal Power Level (-dBm) 25 10 Transmit Signal Power Level (-dBm) 16 11 Round Trip Delay (msec) 4 Press any key to continue; ESC to quit. Description Status --------------- ------------ 12 Near Echo Level (-dBm) NA 13 Far Echo Level (-dBm) NA 14 Transmit Frame Count 3 15 Transmit Frame Error Count 0 16 Receive Frame Count 0 17 Receive Frame Error Count 0 18 Retrain by Local Modem 0 19 Retrain by Remote Modem 0 20 Call Termination Cause 0 21 Robbed-Bit Signaling 00 22 Digital Loss (dB) 6 23 Remote Server ID 4342C3
Each of the line items in the ATI11 result is explained next:
1. V90, 56K (K56flex), V.34, or V.32 depending on the type of connection negotiated.
2. Initial upstream rate
3. Initial downstream rate
4. Current or final upstream rate
5. Current or final downstream rate
6. LAPM or MNP or None, depending on V.42 negotiation
7. V42bis or MNP or None, depending on V.42 negotiation
8. Mean-square error of received downstream signal. Difference between received constellation point and reference decision point. This is a dimensionless decimal number, only valid during a call. Higher numbers are worse. There's no absolute threshold of goodness; it depends on the downstream data rate. The number varies during a call, so it can be useful to sample it a few times.
9. The received signal power, although labeled -dBm, is only a relative measure for comparing calls to/from different locations. Only valid during a call.
10. Upstream transmit signal power.
11. Round-trip delay reads differently for different server types, so can be used as a relative measure to compare connections to the same type of server.
12. Echo levels are valid for V.34 only.
13. Echo levels are valid for V.34 only.
14. Number of LAPM frames sent upstream during this call.
15. Number of REJ frames received at the analog client modem.
16. Number of LAPM frames received by client during this call.
17. Number of frames received in error by the client.
18. Number of retrains or rate renegotiations requested by this modem.
19. Number of retrains or rate renegotiations requested by remote modem.
20. Reason for call ending, only valid after call ends:
0 = Local modem command: ATH, DTR drop
21. For PCM modes only, a hexadecimal 6-bit pattern of T1 frames with robbed-bit signaling.
22. For PCM modes only, the downstream digital loss.
23. For K56flex only, the V.8bis info sent by the server. Meaning is defined at the server and by convention. Example above is from Ascend MAX in mu-Law.
It is sometimes useful to be able to limit the maximum connect speed, particularly if you are getting disconnected frequently.
Add these commands to the end of your init string.
For V.34 (188.8.131.52) To limit the upstream V.34 rate, use S37: S37 = 0 auto rate S37 = 1 reserved S37 = 2 1200/75 bit/s (V.23) S37 = 3 300 bit/s S37 = 4 reserved S37 = 5 1200 bit/s S37 = 6 2400 bit/s S37 = 7 4800 bit/s S37 = 8 7200 bit/s S37 = 9 9600 bit/s S37 = 10 12000 bit/s S37 = 11 14400 bit/s S37 = 12 16800 bit/s S37 = 13 19200 bit/s S37 = 14 21600 bit/s S37 = 15 24000 bit/s S37 = 16 26400 bit/s S37 = 17 28800 bit/s S37 = 18 31200 bit/s S37 = 19 33600 bit/s For K56flex
To force a particular K56flex downstream rate, use S-register S38. S38=0 disables K56flex, and may allow a more reliable V.34 connection. S38=1 default allows the modem to select the downstream rate automatically. Other values of S38 force the downstream rate, with fallback to V.34 if unsuccessful at the configured rate:
S38=0 Disable K56flex S38=1 Automatic rate selection (default) S38=2 32 kbit/s S38=3 34 kbit/s S38=4 36 kbit/s S38=5 38 kbit/s S38=6 40 kbit/s S38=7 42 kbit/s S38=8 44 kbit/s S38=9 46 kbit/s S38=10 48 kbit/s S38=11 50 kbit/s S38=12 52 kbit/s
The number of robbed-bit signaling (RBS) frames detected decreases the true DCE rate per the following table:
RBS links Rate hit (kbit/s) 0 0 1 2 2 4 3 4 4 6 5 8 6 8
For example, if S38=10 and there are 3 RBS links, the K56flex downstream rate will be 48-4=44 kbit/s. The exception to this is for 32 kbit/s and 34 kbit/s, which are the true rates regardless of the number of RBS frames detected.
To force a particular V.90 downstream rate, use -V90 = <n> -V90=0 will disable V.90 -V90=1 will enable V.90 Auto Rate (default Value) -V90=X - controls the downstream rate -V90? - Shows the current value -V90=? - Shows the range [0-21] The table below shows the possible values: "AT-V90=X" Downstream Rate 0 V.90 disabled 1 Auto Rate (default) 2 28000 3 29333 4 30666 5 32000 6 33333 7 34666 8 36000 9 37333 10 38666 11 40000 12 41333 13 42666 14 44000 15 45333 16 46666 17 48000 18 49333 19 50666 20 52000 21 53333
Many thanks to Lucent Technologies for their contributions!
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