Installing an ISDN line Telephone repairman is sitting next to the phone jack. Repairman says, "First we need to make sure your phone line is connected to our network." Repairmen hands Dilbert a cordless phone. Repairmen says, "I'll yank the wire while you listen for a "whump" sound at the central office." Central office full of pipes. Wires spill out of one of the pipes. Man holding one of the wires is listening to the phone which is off the hook. Over the phone Dilbert is heard. Dilbert says, "I heard something."