Home Numbering Plan Area Code (HNPA)
The | local | area code. The area code does not have to be dialed to call numbers within |
the | local | geographical area. |
Immediate-Start Tie Trunk
After establishing a connection with the distant switching system for an outgoing call, the system waits a nominal 65 milliseconds before sending the digits of the called number. This allows time for the distant system to prepare to receive the digits. Similarly, on an incoming call, the system has less than 65 milliseconds to prepare to receive the digits.
In-Use Lamp
A red lamp on a multiline voice terminal that lights to show which call appearance will be selected when the handset is lifted or which call appearance is active when a user is
Intercept Tone
An alternating high and low tone; indicates a dialing error or denial of the service requested.
Interface
A common boundary between two systems or pieces of equipment.
Internal Call
A connection between two users within the system.
LDN: (Listed Directory Number)
LED: (Light Emitting Diode)
Loop Start Trunk
After establishing a connection with the distant switching system for an outgoing call, System 25 waits for a short period of time before sending the digits of the called number. On incoming calls, the received request for service is sufficient to cause the call to route to a predetermined destination, normally the system attendant group. No digits are received.
MET: (Multibutton Electronic Telephone)
Modem
A device that modulates and demodulates signals transmitted over a communications path. Used to connect Data Terminal Equipment to the system’s analog ports. The system provides a pooled modem conversion resource (12 resources maximum per
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