A Core Competence Product Evaluation
How Well Does It Work?
We connected reliably at 9600 bps each time we tried from within a GSM serving area. With GSM, you're either within a serving area or you aren't - there are no fuzzy edges where services fades in and out, where packet data services try and retry and retry again. The continuity offered by circuit-switched data services plays well with applications that transfer batches of data - downloading files, web pages, and email attachments. As our trial progressed, we found ourselves relying on wireless to read email more frequently, enabling us to stay in touch with clients during business hours rather than checking messages only at night, when tethered to a hotel phone jack. Wireless connectivity also allowed us to send urgent email messages when no other solution was available.
But roamers beware: GSM coverage has not yet extended very far beyond metropolitan areas. Roaming around the San Francisco Bay area, we had connectivity wherever we looked. Roaming around Philadelphia, often at the edge of Omnipoint's GSM serving area, we found coverage only about half the time we checked. Your own experience in other locations may vary. We suggest carefully inspecting GSM coverage maps to ensure you'll have service where you need it.
When it comes to raw speed, today's GSM circuit-switched data services are slow. Repeating file transfer throughput tests run previously for the same modem over wireline analog, we downloaded both compressible and non-compressible files at a consistent 7.5 Kbps. In practical terms, this speed is fine for retrieving and sending email without large attachments. It was also usable to check out a couple of web pages in a pinch. But it took an hour to download a anti-virus software from the web, and we wouldn't want to spend a lengthy period of time surfing the 'net this way. High-speed circuit-switched data (HSCSD) promises to yield 14.4 Kbps over a single channel and use multi-channel bonding to produce 28.8 Kbps later this year. GPRS (GSM packet-switched data) will bring speeds up to 115 Kbps by the year 2000.