The first customers of Apple's iPhone won't be traveling in the fast broadband lane much of the time. Transmission speeds over Cingular Wireless's Edge data network often drop down to dial-up speeds.

In this week's formal unveiling of the iPhone, Cingular focused on Apple's voice mail and made no mention of data speeds. The company didn't immediately respond to requests for comment on data speeds.

"iPhone's unique Visual Voice Mail was co-developed by Apple and Cingular," according to a statement from Cingular. "Visual Voice Mail makes voicemail as fast and convenient as e-mail by allowing users to go directly to any of their voice messages without listening to any of the prior messages."

Cingular's Edge network provides nationwide coverage at average data speeds between 75 Kbps and 135 Kbps, according to Cingular's Web site. By comparison, the CDMA EV-DO Rev A network being rolled out by Sprint has speeds of 450 Kbps to 800 Kbps. Sprint says its EV-DO network already covers several cities and will be deployed nationwide in the third quarter. Verizon Wireless also has rolled out network segments using CDMA EV-DO technology. The other major GSM provider in the United States, T-Mobile, uses Edge technology.

The iPhone also offers something of a departure for mobile phone service providers in that it has Wi-Fi capability, which can deliver high-speed data access. The phone reportedly switches seamlessly and automatically between Edge and Wi-Fi, depending on what's available. But users will have to find a Wi-Fi hotspot to use the high-speed capability.

Cingular says it will begin offering the Apple iPhone nationwide in June. Apple's decision to use Cingular's Edge (Enhanced Data Rates for GSM Evolution) underscores the ongoing battle between the European-developed GSM standard and Qualcomm's various CDMA flavors. While Qualcomm struggled for years to bring its CDMA technologies to market, GSM providers captured most of the worldwide mobile phone service provider market and they have moved to lock it up for the future.

When advanced CDMA technologies finally made it to market, they were more robust than most GSM offerings. Qualcomm says its EV-DO networks can reach peak data rates of 3.1 Mbps on the forward link, and 1.8 Mbps on the reverse link.

Cingular and other GSM-based service providers are working on technologies such as High-Speed Downlink Packet Access (HSDPA) to boost their network data speeds to at least parity with EV-DO, although they aren't expected to be available in time for the iPhone rollout.

Will data speed rates make any different to iPhone users?

One longtime Apple cheerleader, influential personal technology reviewer Walter Mossberg of the Wall Street Journal, heaped praise on the iPhone Thursday, although he mentioned it runs on the "relatively slow" Edge network. Mossberg has evaluated competing GSM and EV-DO technologies and has said Edge is a "drastically slower alternative that constantly reminded us that we were using a pokey mobile device.

"if you're in the market for a smartphone and can afford $499, you might want to wait until June for the Apple iPhone," he wrote. "The Apple entry is so full of promise that anyone buying a smartphone in 2007 should at least wait for the full reviews and a chance to try it out."

Only then will potential customers be able to judge whether the relatively slow data speeds are offset by the other attractive features of the iPhone.