When the Dust Settles
by Stuart Baker
Stuart Baker Software develops telecommunications software for OS/32 and IBM PC's. This necessitates keeping up with developments in the modem market place. The market place is changing so rapidly that considerable effort is required to stay current.
Now you can purchase 300/1200 bps modems for under $100 and 300/1200/2400 bps modems for under $200. These are astonishing prices considering only a few years ago I paid over $1100 for a manual dial 300/1200 bps modem.
Hayes has made an impact on the market place. Their AT command set is the de-facto standard for the industry. Almost every modem manufacturer is offering the "industry standard AT command set." At last there is a standard that every one is following. This allows you to perform auto dialing with programs like Passport on a wide variety of different manufactures modems.
Thanks to standards like CCITT V.22 bis, all of the 2400 bps modems communicate with each other. It is comforting to know you can purchase any 300/1200/2400 bps modem with the assurance that it communicates with everyone. Even the new breed of error correcting modems maintain compatibility by functioning automatically with non error correcting modems.
If everything is so compatible in modem land, then why the title of "When the Dust Settles?" What I am addressing is the lack of approved standards and compatibility among the new breed of 9600 bps modems. The CCITT V.32 standard is being developed to address 9600 bps full-duplex communications and error correcting. Until a standard is approved, the industry has no direction. This is leading to chaos, as many manufacturers are coming out with modems in the hopes their entry becomes a standard. Thus virtually all 9600 bps modems are islands onto themselves. A Hayes only communicates with another Hayes, a USRobotics only communicates with another USRobotics, etc. This is very undesirable.
In addition to the lack of compatibility one must be very careful when examining the features of this new breed of modem. Terms like "Terminal full-duplex" and "Full-duplex asymmetrical" are very misleading. These modems are not truly full-duplex as the manufacturer would like the casual observer to believe. In environments like OS/32 that use remote echo, some of these modems exhibit very poor performance. Also, some types of file transfer protocols are expecting true full-duplex operation to function properly. Be sure to and test the performance of these modems before making a purchase.
If you need to move large quantities of data, the 9600 bps speed may sound like the perfect solution. Don't move to quickly. Check out your file transfer throughput with the new modems before making any purchase decisions. There is an undesirable interaction between file transfer protocols and the modems internal error correction procedures. Throughput on some of the 9600 bps modems is less than a 2400 bps modem without error correction. Therefore you can not calculate cost savings by simply dividing your current phone bill by 4.
In conclusion, unless you can justify writing off the complete cost in less than one year, delay your purchase for a while. With the current incompatibility between various manufacturers modems, establishing a standard will most likely obsolete any hardware now available. If you must make an immediate purchase my leaning is toward the modems that are true V.32 full duplex. In addition, by the time the dust settles, file transfer protocols that take full advantage of the new modems should exist.
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