MadHack
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56k modem's top speeds.
I heard that a 56k modem can only receive at that speed but transmit at 33.6k. Is it true? Does this apply to X2 technology modems or K56 flex technology modems?
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dew,
I'm sorry but it just isn't so. The 56K technology (both USR and Rockwell's) are asymmetric. The downlink speed has the _potential_ for 56K but the uplink is 28.8K. Tt is also against current FCC rules to operate the downlink at > 53K! If you are measuring speeds in excess of this you are measuring wrong or are measuring bit-rate including v.42 compression and not the signalling rate.
The 3COM/USR web site has an excellent paper on this topic at:
http://x2.usr.com/technology/whitepapers.html
I'm sorry but it just isn't so. The 56K technology (both USR and Rockwell's) are asymmetric. The downlink speed has the _potential_ for 56K but the uplink is 28.8K. Tt is also against current FCC rules to operate the downlink at > 53K! If you are measuring speeds in excess of this you are measuring wrong or are measuring bit-rate including v.42 compression and not the signalling rate.
The 3COM/USR web site has an excellent paper on this topic at:
http://x2.usr.com/technology/whitepapers.html
I'm going to toss my $0.02 in as well. 56K modems will also only connect to digital equipment at this speed. There can only be one analog to digital conversion (your phone line to your local switch)thus 56k to 56k is really 28.8 or 33.6. Also, it's true they are 56k download only, and the FCC limits this to 53k (if I were a betting man, I'd bet you couldn't tell the difference). One more thing, there are competing technologies out there so make sure your ISP supports the brand of modem you pick up.
JHance, I stand corrected! We have a T-1 here, so the only testing we have done is when we connect new systems to the lines that sprint has run to our facilities here, which I believe are digital/fibreoptic, but I'm not certain of that (haven't had any reason to check it until you mentioned it). Thanks for the info though, now my curiosity has been piqued.
Dennis
Dennis
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Yeah. I read about that. A 56k can downlink at the maximum rate of 56kbps but only uplink at 33.6. When the other party sends the data to us at 56k, they use a T1 line connected to the telecom network cloud. That's how it's possible for them to uplink stuffs to us at 56k. :)
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