If you use long-distance telephone lines to set up network bridges, remotely control PCs, or access leased lines, you should consider one of these 28.8-Kbps modems. Under the best conditions, when communications links are unimpaired and when modems on both ends of the line can talk to each other at 28.8 Kbps, this setup translates directly into lower telephone charges.
However, until V.34 is formalized and widely implemented, there is no guarantee that two of today's V.34 modems will be able to communicate at their highest speed. In fact, our interoperability tests show that V.34 modems sometimes have to drop all the way to V.32bis rates of 14.4 Kbps--half their maximum speed--to communicate with V.34 modems from other vendors using a different chip set.
For example, the V.34 modems that used the Rockwell chip set wer
e able to communicate with each other at 28.8-Kbps rates. However, when we connected them with V.34 modems that used an alternative chip set, such as Racal Datacom's or Motorola's modems, communication dropped to 14.4 Kbps. The same was typically true when we connected V.34 modems with V.32terbo models. The ZyXel U-1496E Plus, which uses a proprietary protocol for 19.2 Kbps, achieved that speed only when connected to another ZyXel modem; otherwise, it communicated at 14.4 Kbps.
While the majority of the slower V.32terbo modems negotiated the impaired lines without much difficulty, the V.34 group was a different story. Only one V.34 modem (Boca's V.Fast Class External Bocamodem) completed all six lines without a problem. Of the 11 remaining V.34 desktop modems, six needed revisions to their firmware, and five needed special commands (most of which were undocumented) added to the setup string. (Vendors promised that any firmware or setup-string changes made available to us for testing would be offered to
the general public via a BBS.)
Based partly on its impaired-line performance, the Bocamodem ranked high in the Best Overall evaluations. In terms of speed, this modem can't compare with the first-place Hayes Optima, but the Bocamodem supports a wide variety of protocols, offers both Class 1 and Class 2 fax, has a five-year warranty, and sells for a relatively low price of $345.
The Zoom ZVFX28.8 is the lowest-priced ($299) V.34 modem we ranked. It had trouble with the long local loops as well as with the satellite lines. Our calls to the manufacturer led to new EPROMs, but the satellite lines still proved to be troublesome. When we manually dropped the modem's speed to 19.2 Kbps, as recommended in the manual, the modem was able to complete the tests.
The Hayes Optima and Bocamodem are noteworthy because they ship with their own serial cards. The Boca card contains a 16550 UART (universal asynchronous receiver/transmitter), which is necessary if your system has an older UART, such as the
8250 or 16450. The benefit of the 16550 is in caching: The chip can hold up to eight characters during processing. The Hayes card, on the other hand, is an accelerator that boosts the DTE (data terminal equipment) rate of the modem to 230.4 Kbps.
The Supra FAXmodem 288 had the cleanest, easiest-to-read documentation of these modems. Commands were easy to find, and the manual included an index, a table of contents, and clear setup instructions.
The General Datacomm Desk Top V.F 28.8 is geared for network switching environments. It has a built-in serial interface that provides for DTE communication at speeds above the PC limit of 115.2 Kbps. The drawback to designs like this is a reliance on protocols that allow highest-speed communication only with like modems.
To be con-sidered for Best Overall, a 28.8-Kbps modem had to offer data and fax communications. We considered all the products in this group and priced under $400 in our Low Cost category. Our Data Only category considered all 12
V.34 desktop modems.
Rankings for This Category
Performance 75%
Features 15%
Ease of Use 10%
Need the highest speed?
BEST OVERALL
Hayes Optima 28800 V.FC + Fax
Although this modem's one-way data transfers were only slightly faster than the other modems ranked here, the two-way performance was an impressive 23 percent faster than the first runner-up. This is partially attributable to the Optima's 16-KB dictionary, which is eight times larger than most of the other modems. The large dictionary speeds up data compression to give the Optima a performance edge. The modem is easy to set up, although we needed to tweak its initialization string to achieve acceptable impaired-line scores. Weaknesses include sparse documentation and no mainframe and leased-line support.
THROUGHPUT (BYTES PER SECOND)
PRICE ONE-WAY
TWO-WAY IMPAIRED LINES
BEST Hayes Optima 28800 V.FC + Fax $579 7413.4 7260.2 2298.0
RUNNER-UP Boca V.Fast Class External $345 6865.9 4781.6 2173.5
RUNNER-UP Microcom DeskPorte Fast $499 6868.1 5411.4 2215.9
RUNNER-UP Zoom ZVFX28.8 $299 6881.4 5855.1 2176.9
RUNNER-UP Supra FAXmodem 288 $399 6790.7 4227.3 1352.0
RUNNER-UP Practical Peripherals
PC288LCD V.FC $429 6825.4 5331.0 1440.6
INTEROPERABILITY (%)
EASE
OF MAXIMUM
CALL ANSWER FEATURES USE DTE*
BEST Hayes Optima 28800 V.FC + Fax 31 35 ### ### 230.4**
RUNNER-UP Boca V.Fast Class External 38 37 #### #### 115.2
RUNNER-UP Microcom DeskPorte Fast 38 38 ### ###
115.2
RUNNER-UP Zoom ZVFX28.8 35 27 ### ### 115.2
RUNNER-UP Supra FAXmodem 288 35 31 ### #### 115.2
RUNNER-UP Practical Peripherals
PC288LCD V.FC 38 38 ### ### 115.2
Key
Ease of Use:
Poor #
Fair ##
Good ###
Excellent ####
* Kbps.
** When used with Hayes accelerator card.
Looking for a high-speed bargain?
LOW COST
Boca V.Fast Class External Bocamodem
This $345 modem transmitted our compressed file unidirectionally over a normal line at a rate of almost 6900 bytes per second. Although slower than the Hayes Optima, this speed is still faster than the fastest V.32terbo for about $60 less. It was also the simplest of the V.34 modems we tested because it required no setup-string tweaking or firmware updates. The Zoom ZVFX28.8, while faster, ranks second due to troubles during our impaired-line testing.
THROUGHPUT (BYTES PER SECOND)
PRICE ONE-WAY TWO-WAY IMPAIRED LINES
BEST Boca V.Fast Class External $345 6865.9 4781.6 2173.5
RUNNER-UP Zoom ZVFX28.8 $299 6881.4 5855.1 2176.9
RUNNER-UP Supra FAXmodem 288 $399 6790.7 4227.3 1352.0
RUNNER-UP Cambridge DataSystem VFCXE2814 $299 6025.9 5634.2 842.0
RUNNER-UP GVC FM1441288V $379 6707.5 6694.8 1687.9
INTEROPERABILITY (%)
EASE
OF MAXIMUM
CALL ANSWER FEATURES USE DTE*
BEST Boca V.Fast Class External 38 37 #### ### 115.2
RUNNER-UP Zoom ZVFX28.8 35 27 ### ### 115.2
RUNNER-UP Supra FAXmodem 288 35 31 ###
#### 115.2
RUNNER-UP Cambridge DataSystem VFCXE2814 38 31 #### ### 115.2
RUNNER-UP GVC FM1441288V 27 38 ### ### 115.2
Key
Ease of Use:
Poor #
Fair ##
Good ###
Excellent ####
* Kbps.
** When used with Hayes accelerator card.
If only data is required...
DATA ONLY
Hayes Optima 28800 V.FC + Fax
No surprises here. Even when excluding its fax capabilities, the Optima's speed and ease of use make it the top choice for data-only applications. Note: The General Datacomm's poor interoperability for faster-than-14.4-Kbps communications was also apparent in other modems using proprietary chip sets. Its performance was average for V.32bis and slower communications.
THROUGHPUT (BYTES PER SECOND)
PRICE ONE-WAY TWO-WAY IMPAIRED LINES
BEST Hayes Optima 28800 V.FC + Fax $579 7413.4 7260.2
2298.0
RUNNER-UP Microcom DeskPorte Fast $499 6868.1 5411.4 2215.9
RUNNER-UP Boca V.Fast Class External $345 6865.9 4781.6 2173.5
RUNNER-UP Zoom ZVFX28.8 $299 6881.4 5855.1 2176.9
RUNNER-UP General Datacomm
Desk Top V.F 28.8 $1095 6084.8 6000.7 2104.7
INTEROPERABILITY (%)
EASE
OF MAXIMUM
CALL ANSWER FEATURES USE DTE*
BEST Hayes Optima 28800 V.FC + Fax 31 35 #### ### 115.2**
RUNNER-UP Microcom DeskPorte Fast 38 38 ### ### 115.2
RUNNER-UP Boca V.Fast Class External 38 37 #### ### 115.2
RUNNER-UP Zoom ZVFX28.8 35 27 ### ### 115.2
RUNNER-UP General Datacomm
Desk Top V.F 28.8 0
0 ## #### 128.0
Key
Ease of Use:
Poor #
Fair ##
Good ###
Excellent ####
* Kbps.
** When used with Hayes accelerator card.
The Best V.34 Modems
