Funny Service call

I was having trouble with my computer.
So I called Bruce, the computer guy, to come over.
Bruce clicked a couple of buttons and solved the problem.
He gave me a bill for a minimum service call.

As he was walking away, I called after him,
"So, what was wrong?"
He replied, "It was an ID ten T error."
I didn't want to appear stupid, but
Nonetheless inquired, "An ID ten T Error?
What's that . In case I need to fix it again?"

Bruce grinned.... "Haven't you ever heard of an ID ten T error
before?"

"No," I replied.

"Write it down," he said, "and I think you'll figure it out."

So I wrote it down.
I D 1 0 T