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56K Modem Troubleshooting Guide

Interoperability: V.34, x2, K56flex 1.0 and 1.1 and V.90 33.6 or less when dialing a Livingston Portmaster K56flex Connect problems or slow connects when dialing a 28.8/33.6 modem How can I enable or disable x2 and/or V.90? How can I enable or disable K56flex and/or V.90? 33.6 or less when dialing a Livingston Portmaster K56flex Livingston Portmasters use Lucent chips which implement K56flex 1.1. Some Rockwell-based K56flex modems still use K56flex 1.0. Understanding the version numbers The 1.0 and 1.1 terminology is a little confusing, because it does not match the firmware version numbers. To determine your modem's K56flex version, type "ATI3" in a terminal program and press the enter key. Here's how to match the ATI3 response to the K56flex version: ATI3 result K56flex version - - - - - - - - - - - - - - - - - - - - - less than 1.0 1.0 1.0 or greater 1.1 The actual result will look something like "V0.519DHY-K56_DLS". The "V0.519" is the version number in this case, indicating that this is K56flex 1.0 (old) firmware. The modem manufacturer will need to issue a firmware update to upgrade your modem to K56flex 1.1. Until then, you'll be limited to V.34 speeds (up to 33.6K). Check the firmware updates page to see if there is a new version for your modem. You can easily tell if you're dialing a K56flex 1.1 modem because of the extra tone at the beginning of the connection sequence. You will need to turn on your modem speaker to hear the sound, or you can simply call your ISP with a telephone and listen for the sound. Download a WAV file recording of a K56flex version 1.1 server Connection problems or slow connects when dialing a 28.8 or 33.6 modem If you have a 56K modem but you're dialing into a V.34 modem bank, your modem will still try to negotiate a 56K connection, even though it's impossible. You may want to use one of the commands below to tell the modem to not attempt a 56K connection. How can I enable or disable x2 and/or V.90? The answer depends on whether your modem supports only x2 or x2 and V.90. For modems that use x2 only These go at the end of your current init string. S32=32 (for Sportster: disables x2) S32=34 (for Sportster: disables x2 and enables V.8 mode) S58=1 (for Courier) In addition, some people have had success with these commands. s15.7=1 &N16&U8 &N16 S32.5=1 For modems that support x2 and V.90 x2 on, V.90 off x2 off, V.90 on Both off Both on* Sportster** S32=66 S32=34 S32=98 S32=2 Courier S58=32 S58=1 S58=33 S58=0 * Using AT&F1 in the init string automatically enables both protocols. **Non-U.S. Robotics modems that use x2 generally use the same commands as the Sportster How can I enable or disable K56flex and/or V.90? The command depends on whether you have a Rockwell-based or Lucent-based modem. Rockwell chipset modems For Rockwell-based K56flex modems that do not also support V.90, add +MS=11,1 to the end of your modem init string. For K56flex modems that have been upgraded to V.90, or that support V.90 and K56flex simultaneously, use these commands at the end of your modem init string: These commands were provided by Jay Price, an application engineer with Computer Peripherals International, and by Rockwell (now Conexant). For most Rockwell chips (except on PCI card modems): V.90 preferred (K56flex will still work)* +MS=12,1 V.90 only, K56flex and V.34 disabled* +MS=12,1,34667,56000 K56flex preferred (V.90 will still work)* +MS=56,1 K56flex only, V.90 and V.34 disabled* +MS=56,1,34000,56000 Disable V.90 and K56flex, use V.34 (28.8/33.6) +MS=11,1 * Remember that a Rockwell-based K56flex modem upgraded to V.90 no longer supports K56flex. For an explanation, see If I upgrade my K56flex to V.90, will I still be able to connect to K56flex modems at 56K speeds? For Rockwell HCF chips (used on PCI card models): V.90 preferred (K56flex will still work) +MS=V90 K56flex preferred (V.90 will still work) +MS=K56FLEX Disable V.90 and K56flex, use V.34 (28.8/33.6) +MS=V34 Lucent chipset modems For Lucent-based K56flex modems that do not also support V.90, add S38=0 to the end of your modem init string. For Lucent-based modems that do support V.90, use one of the following strings. For Apollo (LT Win Modem) and Mars (LT PCI Win Modem) chipsets: Enable V.90 -V90=1 Disable V.90 -V90=0 See current -V90 setting with explanation -V90? in a terminal Enable K56flex S38=1 Disable K56flex S38=0 For Venus chipsets (mostly used in external modems): K56flex only (V.90 disabled) S109=0 K56flex or V.90* S109=1 V.90 only (K56Flex disabled) S109=2 Disable K56flex and V.90 (use V.34) S38=0 * 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.

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