Modem Tutorial Index
Buying a High-speed Modem
V.32 and V.32bis modems are clearly the standards of high-speed modems today. You should buy a V.32 or a V.32bis modem unless
A V.32bis modem is faster than a V.32 modem but it also costs more. Should you pay the extra for the speed difference? That depends on two factors: what's the price difference and how do you want to reach the remote system. If the price difference is $50, I would buy the V.32bis modem. But what if the price difference is $200?
Assuming the remote system support V.32bis, a V.32bis modem will pay for itself rather quickly if you are placing long distance calls to the remote system. However, it may be more cost-effective for you to use some packet-switching networks to reach the remote system by calling a local number. A V.32bis modem will be wasted since none of the packet-switching networks currently support V.32bis. In fact, they are just starting to offer 9600 bps access service. Part III of "The Joy of Telecomputing" provides a comprehensive discussion of the issues involved.
Should you buy a modem with a proprietary modulation protocol?
With the exception of the CompuCom SpeedModem Champ, it is generally not a good idea to purchase a modem which only supports a proprietary modulation protocol. If you have to connect to a modem that uses a proprietary modulation protocol, you should consider getting a modem that supports dual modulation protocols (USR Courier Dual Standard, Telebit 2500 or 3000, Hayes Ultra).
Should you buy the SpeedModem Champ?
It certainly costs much less than even the least expensive generic V.32 modem in the market today. Assuming the systems you are calling support both V.32 and the CompuCom Champ modems, should you save the money and buy the Champ?
Unfortunately, there is no clear-cut answer to the question. The answer again depends on how you are going to reach the remote systems. If you want to reach the remote systems via a packet-switching network, the CompuCom Champ may not be a good choice.
The CompuCom Champ is generally not supported by packet-switching networks (The only company that supports the CompuCom Champ is Connect-USA). As a result, you will only be able to connect at 2400 bps with the packet-switching networks. You would be forced to place a long distance call if you want to connect at 9600 bps. See Part III of "The Joy of Telecomputing" for the various issues involved.
Should you buy a 2400 bps modem with V.42bis?
If you are thinking of purchasing a 2400 bps modem with V.42bis data compression, think again.
We have mentioned earlier that V.42bis and MNP-5 are useless for downloading compressed files. There is one more reason why a 2400 bps with V.42bis is generally not useful when you are calling commercial online services or BBS.
Online services and BBS usually have separate phone numbers for 2400 bps and high-speed modems. Most of them do not support V.42bis on their 2400 bps lines. Therefore, you won't be able to make a connection with V.42bis if you call their 2400 bps modem lines.
Couldn't you call their 9600 bps lines? Well, not really. Commercial online services, as well as many bulletin board systems, typically do not allow you to call their high-speed modem lines with a 2400 bps modem. You won't be able to make a connection even if you try.
You should seriously consider the CompuCom SpeedModem Champ instead of a 2400 bps modem with V.42bis. The CompuCom Champ will probably give you much more for your money (especially if you need to pay more than $100 for the V.22bis/V.42bis modem).
Beware of the Ads
Current V.32 modems typically support MNP 2-5 and V.42/V.42bis. However, there are still some earlier models of V.32 modems in the market which
When a modem is said to offer a 9600 bps speed (or throughput), it may mean several things:
Modem Tutorial Index