V.90 FAQ and Information



Document ID: 98050242

 

Posted Date: 1999-05-26

 

Last Updated: 1999-05-28

 

Distribution: View Public Website

 

Applicable Models
Satellite All
Qosmio All
Portege All
Tecra All
Satellite Pro All

 

Information


Overview - What is V.90?
An ITU (International Telecommunications Union) standard (approved inFebruary1998) for a modem that communicates at 56 Kbps downstream and 33.6Kbps upstream. V.90 is the international 56K analog modem standard. It isintended for use only with ISPs (Internet Service Providers) and onlineservices that are digitally attached to the telephone system. Initially, twoincompatible technologies competed in this arena: X2 from U.S. Robotics andK56Flex from Rockwell and Lucent. The V.90 standard resolves theincompatibility between the two 56 Kbps technologies. Such modems can beupgraded to V.90 if they contain software-upgradable memory chips.

How fast are connection speeds of V.90 modems?
With a "reasonably" good phone line and if you are located within 3 1/2miles from your central office (local phone company building), ideally youshould get connection speeds between 40K and 53K. Some lines have impairmentson them, such as digital pads or RBS (robbed bit signaling ), which decreasesthe highest achievable speeds.

Why do some modems support both V.90 as well as either K56Flex or X2?
This is to insure compatibility with your existing Internet ServiceProvider (ISP). As ISPs upgrade their modems, these types of modems will beable to switch automatically into V.90 mode, but until then will continue tooperate in K56Flex or X2 mode. These types of modems support TWO 56Kprotocols, V.90 plus another, X2 or K56Flex.

Can I upgrade my modem to V.90?
If your older modem contains software-upgradeable memory chips, and yourmanufacturer is providing the new code to do so, yes you can upgrade to runthe V.90 protocol.. Name brand modem manufacturers will provide upgradefirmware and instructions on their website. (If you have a ROM-based modem, itwill not be upgradeable.) If you have a generic brand modem it may bedifficult to impossible to attain the flash upgrade.

However, there are several issues to keep in mind. Some of the olderpre-standard Rockwell modems, while flash upgradeable to the new standard, canonly hold one protocol at a time. Loading V.90 code into these types of modemswill turn the 56K modem into a 33.6! If your modem can only run V.90, itcannot connect in high speed PCM (pulse coded modulation) mode to a K56FlexISP, until the ISP deploys V.90. If your modem is working fine now in X2 orK56Flex mode, leave well enough alone.

The following are V.90 modem drivers for Toshiba internal modems:

V90_56K.EXE
Windows 95/98 V.90 Modem Driver version 5.28-RC5
Applicable Models: Satellite 254x, Satellite Pro 490, Portege 320, 70xx,Tecra 550, 750, 780, 8000

V90_NT4.EXE
Windows NT 4.0 V.90 Modem Driver version 5.28
Applicable Models: Satellite 254x, 4030, 4060, 4080, Satellite Pro 490,Portege 320, 70xx, Tecra 550, 750, 780, 8000Note: Toshiba models not listed are NOT V.90 upgradeable.


Why does my 56K modem only connect at 33.6 or lower speeds?
Make sure you are calling a phone number that has a compatible 56K modem atyour Internet Service. Some phone numbers only have V.34 modems on them andyou cannot attain 56K speeds calling these. Make sure you are also calling acompatible line. If your ISP has K56Flex only running, you will not be able toget an X2 modem to connect at K56 speeds and visa versa.

Will V.90 (or X2 or 56Kflex) work when a SLICK is present?
Many homes and businesses are attached to the central office by a "SLICK"or "Subscriber Loop Carrier" system, such as SLC-96 or SLC Series 5. If such asystem is present, the line from a subscriber's phone first goes to a SLC"remote terminal" (which is typically in an underground vault in theneighborhood, in the basement of the office building, etc.). At that point theanalog signal is converted to 64Kbps digital; then 24 of these are put on twopairs (one for sending, one for receiving) and then this goes to the centraloffice. At the central office there are several ways of attaching to theswitch, but in "universal SLC", the 24 signals go to a "CO-terminal", wherethey are de-multiplexed and converted back to analog before attaching to theswitch. A SLICK creates a D to A conversion then an A to D conversion. Thelater A to D conversion will not allow you to get 56K (PCM) rates. None of theprotocols (V.90, K56Flex or X2) will give you 56K rates with the extra A to Dconversion.

What advantages does V.90 have over X2 technology?
When any ISP converts to V.90 lines and you switch over, will you noticeany difference in speed and connection (other than a different modem tone atsign on) over X2? There will probably not be noticeable performanceimprovements. V.90 will give you more universal ability to call other ISPsthat have either 3COM or Rockwell, Lucent, etc. equipment.

Will ISPs claiming to support the V.90 be compatible with pre-V.90 modems?
Pre-V.90 56 Kflex modems and the V.90 modems should work when connectingto an ISP using V.90. If your modem only supports X2, then it will onlyconnect at high speeds to an X2 compatible ISP. The same applies for a K56Flexonly modem. If you flash update your X2 or K56Flex modem to run V.90, then itshould connect to any ISP that has V.90. An X2 only modem will not be able toconnect at high speed to a K56Flex only provider and vice versa.

How do I disable V.90 on my Toshiba internal built-in V.90 modem?
  1. Go Start/Settings/ControlPanel, and double click on the Modem applet.
  2. Under the General tab, highlight the V.90 modem and click on theProperties button.
  3. Go to the Connection tab and click on the Advanced button
  4. Under Extra Settings, type in: -v90=0
    Note: For Toshiba 3COM and Megahertz PCMCIA modems, type in:AT s32=66
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