About bandwidth and modems
Bandwidth over a modem connection can sometimes be difficult to understand. There are two connections to a modem: one from your computer to its modem, and one from the computer’s modem to the ISP’s modem.
The connection speed between the computer and its modem (called the Maximum speed under Control Panel/Modem/General tab/Properties) should be set as high as possible without causing errors. On most computers this is 115200, also written as 115.2 Kb/s.
The connection speed between your modem and the ISP’s, and the compression and error checking, are negotiated between the two modems when they establish the call. In the very best possible case, which is rarely seen, two V.90 (56 Kb/s) modems will be able to connect at 53 Kb/s with compression, and the compression on normal text transfer will average 50%, giving an effective transmission rate of 106 Kb/s. Very highly compressible material could be transferred at the maximum rate of 115.2 Kb/s. Incompressible material like ZIP files could be transferred at a maximum rate of 53 Kb/s.
Our download test transmits an incompressible block of random text. The theoretical maximum transfer speed for this over a V.90 modem is 53 Kb/s, if there was no latency at all on the line–that is, if there was no delay between the times your computer asked for a packet, our computer sent it, and your computer received it. With normal latency, however, transfer speeds are reduced to roughly 85% of the maximum, which for a V.90 modem would be about 45 Kb/s. If your modem connects to your ISP at the more typical 44 Kb/s, then you can expect our test to report about 37 Kb/s on a connection with normal latency.
|
Broadband Product Speed |
Acceptable Average Speed |
|
256kb |
50kbps or higher |
|
512kb |
100kbps or higher |
|
1Mb |
200kbps or higher |
|
2Mb or higher |
400kbps or higher |
