It turns out unlimited data actually does have a limit for wireless carriers in the United States.

An internal memo from T-Mobile US Inc. (NYSE:TMUS) to its staff was published on Wednesday by TmoNews disclosing that the carrier intends to crack down on users who abuse their unlimited 4G LTE wireless data plans.

The document reads:

“T-mobile has identified customers who are heavy data users and are engaged in peer-to-peer file sharing, and tethering outside of T-Mobile’s Terms and Conditions (T&C). This results in a negative data network experience for T-Mobile customers. Beginning August 17, T-Mobile will begin to address customers who are conducting activities outside of T-Mobile’s T&Cs.”

This move by the Bellevue, Washington, carrier comes on the heels of a similar move by Verizon Wireless, which started throttling its unlimited 4G LTE data subscribers on Aug. 1. Managing its bandwidth will become more critical as it looks to use its network in the coming year to distribute live TV.

T-Mobile's policy won't effect customers on metered data plans; it only applies to those on unlimited high-speed plans. As for what’s considered abuse of the service, the carrier includes peer-to-peer (P2P) file sharing applications, continuous Web camera broadcasts, automated data feeds and using the service to send viruses and malware.

For those who are considering running afoul of T-Mobile terms and conditions, the carrier will begin contacting customers starting Aug. 17 with a warning that their speeds may be reduced until the next month if they continue abusing their data connection. Further usage that's considered abuse of the connection will eventually result in T-Mobile throttling, or slowing down, data connections until the next billing cycle.