The C-2000B offers two operational modes for flexibility.

In the Single Line Ring Through Mode, the C-2000B allows single line phones to share a phone line with 1 to 4 door entry phones. Tenants may converse with visitors and activate a contact closure to control gates or strikes. The C-2000B provides door entry phone "Caller ID" and "Call Waiting Caller ID" and a "Call Waiting" tone when the phone line is in use. Tenants can enter at each location by entering a keyless entry code.

In the Analog Station Dial Through Mode, the C-2000B allows 1 to 4 entry phones to share one analog PABX extension or telephone line and place outgoing calls. When a remote party answers, they can converse with visitors and activate a contact closure to control gates or strikes. Monitoring entry phones, forcing door strike relays to operate or remote programming of the C-2000B can be accomplished by calling the analog PABX extension or telephone line connected. Authorized personnel can enter at each location by entering a keyless entry code.

In either operational mode, the secure relay control of the C-2000B prevents the entry phone from dialing the activation code on the keypad of the entry phone or using a hand held touch tone dialer. An auxiliary input is available for connecting a lighted doorbell switch, a common garage door opener / receiver or an auxiliary keyless entry keypad.