Examples from the Web for back channel
But Cantor has since quietly held a series of back-channel conversations with the vice president.
Esfandiari vehemently denies involvement in any type of espionage, back-channel organizations, or the CIA.
Reagan occasionally used her trips to the Soviet Union for back-channel diplomacy.
The back-channel filled up with URLs and phone numbers and email addresses.Makers|Cory Doctorow
The far shore was a full mile away, while between the island and the near shore lay a back-channel perhaps a hundred yards across.The God of His Fathers|Jack London