The N-8000CO allows the N-8000 intercom system to make and receive calls from an analog telephone system. With proper permissions, the outside line can perform any master station function. The N-8000CO allows one-touch dialing from an N-8000 master or door station to an outside line, call forwarding to an outside line and direct dialing into the N-8000 system. Rack mount kit not included. Use TOA MB-15B-BK (one unit per rack space) or MB-15B-J (two units per rack space).