PC Access for Windows Reference Guide

for PC Access for Windows 4.30.158

Modem Speed and Protocol

Bits per second (BPS) is a measure of modem speed. The higher the number, the faster your modem can send information to another modem at the other end of a telephone connection. As modem technology advances, modem speeds tend to increase. Faster modems generally cost more than slower modems. No modem is ever as fast as you want it to be!

To use PC Access or any other communications program, you must know your modem speed in BPS, so you can tell the program what speed to use. (Your computer hardware doesn't provide any way for the software to figure out the right speed automatically.)

If you are curious, here is how you can relate your modem's speed to the kind of work you do. If you are sending text information, divide the BPS by 10 to estimate the number of text characters you can send per second. For example, at 2400 BPS you can send or receive a maximum of about 240 text characters per second. Graphical information contains many more bits of information, so a screen-sized picture takes longer to send than a screen-load of text.

Modems come in a variety of speeds. Modem vendors rate speed in units of "bits per second" (BPS). The standard modem speeds are 2400, 9600, 14,400, and 28,800 BPS. You can usually determine your modem's speed by looking at the documentation that came with it.

You may have a modem with a speed rating of "24/96" or something similar. This means you have a 2400 BPS modem with 9600 BPS FAX capability. Only the 2400 BPS modem speed is available to PC Access or any other communication program. To PC Access, your modem is a 2400 BPS modem. FAX programs can use the higher speed, but only for sending faxes.

The modem name may state or hint at your modem's protocol(s). This can give you a clue about speed. If your modem supports the V.32 protocol, it is a 9600 BPS modem. If it supports V.32bis, it is a 14,400 BPS modem. If it supports V.FC or V.34, it is a 28,800 BPS modem.

Faster modems are usually backward-compatible with all the slower speeds. If your modem documentation lists many protocols that your modem supports, you can determine your modem's highest speed from your modem's highest protocol.

See also DTE Speed.

Last modification date: Friday, January 17, 2003 00:58:55