Google (GOOGL -1.23%) may have given up on trying to beat Apple (AAPL -1.22%) at its own game, but that doesn't mean that Motorola is throwing in the towel quite yet. Rumors have been circulating over the past year that Googorola was working on an "X Phone" that hoped to challenge the iPhone, but Google has reportedly stepped out of the device's development and handed over responsibility to Motorola.

The latest evidence that the "X Phone" is en route to market is an FCC filing detailing the technical cellular specifications of the device. By the looks of it, the presumed "iPhone killer" is set for AT&T's (T 1.10%) network since it's a GSM device with HSPA+ compatibility. The support frequency bands (850 MHz and 1900 MHz) also line up the spectrum ranges that AT&T operates in.

A lot of details about the device remain shrouded in mystery. Google Chairman Eric Schmidt has hinted that Motorola's upcoming pipeline is full of "phones-plus," while Moto's chief designer has expressed interest in a stock Android experience.

Historically, AT&T has been predominantly an iPhone carrier, with Apple's device comprising four out of every five smartphones sold on Ma Bell's network last quarter. Androids undoubtedly comprise the majority of the remaining 20%, but Android has a relatively smaller presence there compared to on Verizon (VZ 0.90%) Wireless.

Google, Motorola, and Verizon formed a powerful trio with the Droid campaign a few years back, and Big Red was the biggest winner. At a time when it lacked the iPhone, Verizon put together a cohesive platform strategy to challenge AT&T's exclusive relationship with the Mac maker. For its part, Motorola continued to generate operating losses, which is still does to this day -- just under Google's multicolored flag.

Motorola currently only has one device on AT&T, the aging Atrix HD that launched last summer. The "X Phone" could refresh Motorola's lineup at AT&T, but would also suggest that Motorola is taking cues from its parent. Google's Nexus program favors GSM models with broad international compatibility, which would give the rumored flagship wider reach.

It may not be a Nexus device, but Moto's upcoming "X Phone" might take some pages out of the same playbook.