He was the one, the only one, who could have known those recognition codes.

Apparently there was a recognition code built into it.

To authorized human authority, as determined by a special recognition code.

The words must have come across as the recognition code for a high officer of this army.

We'd given him a time schedule for the call and a recognition code.

I have the recognition codes, or I'd never have detected it.

Broadcast general alert of our approach and recognition codes, Lieutenant.

He couldn't contact any of the others; Bacarion controlled the recognition codes.

That recognition code had not come through with the others.

Achmed keep the distress call going and add our recognition code.