modems-faq

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VI.9.f. QBlazer

$599. QBlazer is the first portable V.32/V.42bis modem (2.3"x2.4"x2.4"). It 
works with a 9-volt battery for about two hours.

VI.9.g. WorldBlazer

This is the latest and greatest Telebit modem. The WorldBlazer is a dual-mode 
modem that is equipped with Turbo PEP and V.32bis/V.42bis. If you already own 
a Telebit modem, you can purchase a WorldBlazer (for $549) through Telebit's 
Loyalty Pays Again program until June 30, 1992.

Note that T1600, T2500, T3000, and the WorldBlazer all offer the following 
features:

* Built-in support for UNIX UUCP, Xmodem, Ymodem, Kermit file transfer 
protocols 
* Two types of dial-access security: password security and call-back security 
* Remote management and diagnostics

VI.10.  U.S. Robotics Modems

U.S. Robotics has been extremely successful with its high-speed modems. Here 
are its current offerings:

VI.10.a.        Courier HST

This is the modem that made U.S. Robotics the king of PC-based BBS 
communities. Unless you are only going to communicate with other USR HST 
modems, it is probably not a good idea to purchase this unit. The street price 
for a Courier HST is $550-$600.

VI.10.b.        Courier V.32bis

Introduced in 1990, this is a V.32bis/V.42bis modem. It does not support HST. 
The current street price for a Courier V.32bis is $530-$570.

VI.10.c.        Courier HST Dual Standard

This unit is introduced in 1990. If you need to connect to HST modems and also 
want to be able to talk to other V.32/V.32bis modems, this is the modem to 
buy. Its current street price is around $800. The street price for a HST Dual 
Standard is $800. (Note that earlier HST Dual Standard modems only support 
V.32 and not V.32bis.) The HST Dual Standard is considered by many BBS users 
as the best modem money can buy. In March 1992, U.S. Robotics shipped a 
Courier Dual Standard with a 16800-bps HST mode.

The only reservation I have about the Courier modems is their size. The 
external Courier modems are rather bulky: 8.3" wide, 12.65" deep, 1.57" tall. 
I would not want to carry one of these with me when I travel. Incidentally, 
the new Courier Dual Standard is substantially trimmer in size.

VI.10.d.        Sportster 9600 V.42bis

This unit is introduced in 1991. The Sportster  9600 is an entry level 
V.32/V.42bis modem from U.S. Robotics. The list price is $645 for the external 
version. ($595 for the Internal version).

VI.10.e.        WorldPort 9600 V.32

The WorldPort 9600 is a portable pocket modem. Originally made by Touchbase 
Systems, the WorldPort 9600 is a V.32/MNP5 modem. It does not support 
V.42/V.42bis. The WorldPort 9600 works with a 9-volt battery. The list price 
is $699.

V.11.   Zoom Modems

Zoom Telephonics has been making Hayes-compatible modems for quite some times 
now. I have used many Zoom modems in the past and they have proven to be 
reliable and inexpensive.

VI.11.a.        V.32 Turbo

Zoom has been making Hayes-compatible modems for a long time. The V.32 Turbo 
is their entry into the high-speed modem arena. The V.32 Turbo is a 
V.32/V.42bis with a 12000 bps turbo mode which is compatible with a V.32bis 
modem at 12000 bps. Zoom also makes an internal version of the V.32 Turbo that 
features a 16550 UART. PC Connection sells the the internal model for $329.

VI.11.b.        VFX V.32bis and VFP V.32bis

VFX V.32bis is an external V.32bis/V.42bis modem (list price $449). The 
internal version is called VFP V.32bis ($399). Both come with MTEZ (which 
includes ExpressFax) for IBM PC. Zoom also offers a Macintosh version that 
comes with QuickLink II ($449). MacConnection is selling the VFX V.32bis for 
$299.

The Zoom VFX V.32bis and VFP V.32bis support Group3/Class 2 fax.

VI.12.  Things to come

Almost every modem manufacturer makes at least one V.32/V.42bis modem and a 
V.32bis/V.42bis modem now. The price for V.32 and V.32bis modems will continue 
to drop. In the past few months, the price difference between V.32/V.42bis and 
V.32bis/V.42bis modems is diminishing.

Many new modems introduced in the past few months also offer fax capability. 
You can expect modem manufacturers to include fax capability as a standard 
feature in their products if they haven't done so already.

VII.    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

1. Your application requires a high-speed modem with a proprietary modulation 
protocol. In this case, you should consider a dual-mode modem that support 
both the proprietary protocol and V.32 (or V.32bis).

2. You cannot afford a V.32 modem.

VII.1.  Should you pay extra for a V.32bis modem?

A V.32bis modem costs substantially more than a V.32 modem just a few months 
ago. However, the price difference bewteen a V.32bis and a V.32 modem (from 
the same manufacturer) are diminishing. If you're thinking about buying a 
high-speed modem, you should probably look for a V.32bis modem.

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, if you are using 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.

VII.2.  Should you buy a modem with a proprietary protocol?

It is generally not a good idea to purchase a modem which only supports a 
proprietary modulation protocol. You should consider getting a modem that 
supports dual modulation protocols (USR Courier Dual Standard, Telebit 
WorldBlazer, Hayes Ultra) if (i) you have to connect to a modem that uses a 
proprietary modulation protocol, or (ii) you need to have better throughput 
than a V.32bis modem can offer.

VII.3.  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 MNP5 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.

VII.4.  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

1. may not support any error control or data compression protocol (Hayes 
Smartmodem 9600).
2. may support MNP 2-5 but not V.42/V.42bis.
3. may support proprietary data compression protocol (Microcom MNP9).
4. may support V.42 but not V.42bis (Prometheus).

When a modem is said to offer a 38400 bps speed (or throughput), it may mean 
that

1. it is a V.32 or V.32bis modem with V.42bis
2. it is a V.32 modem with proprietary data compression protocol (some 
Microcom modems)
3. it is a high-speed modem with proprietary modulation protocol and V.42bis 
(U.S. Robotics Courier HST)
4. it is a high-speed modem with proprietary modulation protocol and 
proprietary data compression protocol (CompuCom Champ)

An ad that says "USR modem, 38400 bps throughput, V.42bis" does not tell us 
anything except that the modem is made by U.S. Robotics. It could be any one 
of the three Courier modems. It could even be a Sportster 9600.

When a modem is said to offer a 9600 bps speed (or throughput), it may mean 
several things:

1. it is a V.32 modem
2. it is a high-speed modem using proprietary modulation protocol (Hayes 
   V-series Smartmodem 9600, Telebit 1000, etc).
3. it is a 2400 bps modem with V.42bis data compression.
4. it is a 2400 bps modem with 9600 bps fax 
5. it is a 2400 bps modem both V.42bis and fax.


VIII.   Setting Up Software To Work With High-speed Modems

Getting a high-speed modem is only half the battle. You will need to get it to 
work with your communications program. Most communications programs still come 
with settings configured for standard 2400-bps modems.

Since all 2400- bps modems are Hayes-compatible, it is relatively easy to set 
up the software. You simply install the software as if you had a Hayes modem. 
The software usually will work flawlessly. And you don't really have to worry 
about things like the initialization string.

Getting a high-speed modem to work with your software is a different story. 
There is no longer a Hayes standard that everyone follows. Here are some of 
the reasons why you need to know how to configure your high-speed modem to 
work with your communications program.

First, your high-speed modem may not be supported by your software.

Secondly, even if your software supports your high-speed modem, the software 
may not be set up properly.

Finally, even if your software is set up properly, the settings may not work 
all the times.

VIII.1. The Proper Software Setup

When we say that the software is set up properly, we mean that

1. the modem is initialized properly by the communications software, and 
2. the settings of your software match those of the modem

What is the proper way to initialize a high-speed modem? In general, your 
modem needs to be initialized to:

1. Enable V.42bis Data Compression
2. Enable hardware flow control
3. Handle the DTR and CD signals properly (by adding &C1&D2 to the modem 
   initialization string)

We'll use the ATI 9600etc/e modem as an example for our discussions below. The 
initialization string described here is for the ATI modem only. Refer to your 
modem manual for the equivalent initialization string for your modem.

The ATI modem is supported by two popular communications programs: Qmodem and 
HyperAccess 5. Qmodem initializes the modem and also configures itself to use 
hardware flow control. HyperAccess 5 also initializes the modem properly, 
however it does not configure itself to use hardware flow control.

All modems come with default settings preconfigured from the factory. Many 
V.32 high-speed modems are preset to use V.42bis and hardware flow control 
when they are turned on. This optimal configuration enables the modem to 
automatically negotiate a connection with either another V.32 modem supporting 
V.42bis or  MNP protocols (or even a standard modem).

Interestingly enough, not all high-speed modems are configured this way. The 
ATI 9600 etc/e modem, for example, is preset to use V.32 without error control 
or data compression at poweron. (Why? Good question.)

As a result, your communications program needs to issue the appropriate 
initialization string (AT&F2) to set up the ATI modem to use V.32 with V.42bis 
and hardware flow control.

There is another change required. And it has to do with the parameters 
controlling how the modem deals with two of the RS232 signals: DTR (Data 
Terminal Ready) and CD (Carrier Detect).

CD is a signal generated by the modem which is used to indicate its connection 
status. DTR is a signal generated by your computer. DTR is used to enable the 
modem to accept commands from your communications program, it is also used by 
most modems to determine when to disconnect a call.

The factory default setting for DTR tells the modem to ignore change in DTR 
(&D0), and the setting for CD forces CD always on (&C0). These specific 
settings are required by some dedicated dumb terminals in order to communicate 
with the modem. (Virtually all modems use &C0&D0 as the default setting.) 
However, these settings will often cause problems when hanging up the phone 
lines or produce an error message which says the modem is online when it is 
not.

Most communications software programs expect the modem to follow DTR and 
expects CD to follow carrier. "&C1&D2" sets the parameters for the modem to 
handle the DTR and CD signals as expected by most communications programs. 
(However, if you use a Mac, you should use "&C1&D0".)

Therefore, the proper initialization string to use for the ATI modem should be 
"AT&F2&C1&D2" if you have a PC, and "AT&F2&C1&D0" if you have a Macintosh.

VIII.2. Does Your Software Initialize the Modem Properly?

Let's take a look at the initialization stri