The call on the secure line would come any minute now.

Find a secure line if you want to discuss a sensitive matter.

See if you can get a secure line to them.

Asks you to call his service on the secure line.

You don't think I'm smart enough to use a secure line?

"Just like somebody told you it was okay to answer the president's secure line?"

Neither of them would dare use its name, even over a secure line such as this one.

He then asked her to call him back on a more secure line.

He made the call from his office using the old secure line into the Kremlin.

"If making a phone call is all we need to do, there's a secure line back at camp."