T-Mobile USA this afternoon said a software problem caused the outage that left some customers across the country without working wireless service Tuesday afternoon. Here's the full statement from the company.

"On Tuesday, some T-Mobile customers may have experienced service disruptions impacting voice and messaging services. We restored full service to all affected customers later in the day. After investigating the cause, we have determined that a backend system software error had generated abnormal congestion on the network. T-Mobile has since implemented additional measures to help prevent this from happening in the future. We again apologize to those customers who were affected and may have been inconvenienced.”

We've asked a T-Mobile representative whether the company plans to offer discounts, rebates or some form of compensation to make up for customers' inability to use their phones, and we'll update this post when and if we hear back on that issue. We've heard in particular from frustrated T-Mobile customers who needed their phones for election-night activities.

T-Mobile separately promised a $100 "customer appreciation card" to anyone whose data wasn't recovered as part of the earlier Sidekick data outage, although that outage was considerably longer, and much of the data has since been recovered.