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Just ahead of Apple's (Nasdaq: AAPL) iPhone 5 announcement tomorrow, the odd man out among domestic wireless carriers is feeling the sting. T-Mobile has never gotten any official iPhone love, but that's never stopped it from trying to lure owners of unlocked iPhone to its network.

BYOI: Bring Your Own iPhone
The carrier is now kicking up its marketing efforts into high gear, starting on -- you guessed it -- Sept. 12, which is iPhone 5 day. T-Mobile has always been the most open-armed when it comes to devices, featuring its cheaper, no-contract (and no-subsidy) Value plans if a subscriber brings his or her own device. That's always applied to unlocked iPhones, of which T-Mobile claims to have more than 1 million running on its network.

Starting tomorrow, T-Mobile's branded retail stores will even have iPhone 4S demo units available, and its sales staff will be trained on helping bring iPhone users over. The carrier is also developing iOS versions of its own apps for account management and visual voice mail, among others. Both T-Mobile and Sprint Nextel (NYSE: S) have taken to featuring cost savings relative to AT&T (NYSE: T) and Verizon (NYSE: VZ) on their marketing materials, and this time is no different.

Unlockedunlimited

Source: T-Mobile.

T-Mobile's pitch is that an unlocked iPhone user can save $50 per month compared with Ma Bell. The company sums up its strategy in one sentence: "Bring your unlocked iPhone to T-Mobile and save."

Bleeding pink
This is the biggest marketing move by an unofficial iPhone carrier to get its hands on the iPhone. The lack thereof has been a major contributing factor to T-Mobile's woes in recent years. It continues to bleed contract subscribers at an accelerating pace, with 557,000 net lost last quarter.

Metric

Q2 2011

Q1 2012

Q2 2012

Branded contract net customer losses 536,000 510,000 557,000

Source: T-Mobile.

Meanwhile, its three larger rivals continue to activate iPhones mercilessly.

Carrier

Source: SEC filings, conference calls.

All three of them should also be official iPhone 5 carriers starting tomorrow.

Unlimited, unlocked, and un-fast
The technical stars have simply never lined up for T-Mobile. Historically, iPhones have never been compatible with T-Mobile's 3G network, so unlocked users were relegated to 2G data speeds along with any cost savings they were able to enjoy. Starting last year though, T-Mobile began refarming its spectrum to bring 3G speeds to the iPhone.

T-Mobile claims that its internal tests using an unlocked iPhone 4S are able to reach 70% faster download speeds, on average, relative to AT&T's network. Those areas are few and far between, and T-Mobile is far behind the curve on this one.

Of course, that's before you even consider that the iPhone 5 will feature 4G LTE support, where T-Mobile has exactly zero coverage. Its LTE network isn't expected to roll out until next year. T-Mobile has been trading with numerous parties to facilitate its LTE deployment. It's doing a spectrum swap with Verizon as well as Leap Wireless (Nasdaq: LEAP), not to mention the spectrum consolation prize it received from AT&T after the failed merger.

The net result of all of these trading places for T-Mobile will be the eventual rollout of LTE, but for the time being, T-Mobile remains far behind its larger rivals in technical capabilities. With no LTE coverage, there would be little to no point in even offering the iPhone 5 on its network, so it'll be targeting table scraps from older-generation unlocked models, cast aside as buyers upgrade.

T-Mobile wants the iPhone tomorrow, with or without Apple's approval. It just won't be the iPhone 5.

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