AT&T on Wednesday quietly updated its cellphone terms of service to again potentially ban devices like the Slingbox on its network. Having initially pulled earlier changes in what was described as “an error,” the carrier has again modified the terms to specifically prevent “redirecting television signals for viewing on Personal Computers.” It’s not evident whether the phrasing refers to any PC-like device, which could include smartphones, or if it only involves using 3G for the outgoing connection.

Created by Sling Media, the Slingbox primarily serves to share its TV feed or other TV-related devices across both local networks and over cellular connections, including to phones and computers with 3G modems.

Regardless of intent, the news comes as Sling has been waiting over a month for its SlingPlayer iPhone app to be approved without a response from Apple, which is partnered exclusively with AT&T in the US. Other phones like the BlackBerry Bold can already use SlingPlayer on 3G, however.

AT&T hasn’t commented on the change.