What is “DID” and why is it often in quotation marks?
It is not technically correct to generally call it “DID” but everyone does it anyway. “DID” stands for Direct Inward Dial and is a functionality from the phone company (DDI – Direct Dial Inward for non-North Americans). The interface utilized is called Loop Reverse Battery Signaling or LRBS. With this type of service the roles of normal telephone service are reversed. The Central Office goes off hook and dials your equipment.
