Thread: com port
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Old 09-16-2002, 04:49 PM   #10
glc
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Okay - what we now need to do is try to limit the top connect speed. I KNOW this sounds backwards, but what may well be happening is the modem is connecting too fast for the phone line conditions, this is common behavior with generic Rockwell hardware modems. This will result in a lot of bad packets, which error correction will see and request that the packets be retransmitted, which will kill your throughput. Here is how you do this. Go into the advanced modem properties and look for the Extra Settings box. Put this string in there:

+MS=12,,300,44000

This will limit to 44000, see if your download speeds improve. If they do, go down one more notch and keep trying till you find the sweet spot. The next steps down with V.90 are as follows:

42667
41333
40000

etc.

Note that this string modifier MAY not work with your firmware - if you try it and it doesn't connect at all or connects faster than 44000, try this one:

+MS=V90,,,,300,44000

If none of this works, see if you can trade the modem in on a US Robotics external - they seem to work better on impaired phone lines. My line is so bad that I can't get a winmodem or a Rockwell working faster than 28800, but my USR is running well at 37333 with no string modifiers and downloads at 4+ KB/s.
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