Das Panel Link Frame wurde während des Verbindungsaufbaus verwendet, um einen Leerlauf Sender an den District-Selektor Anforderung zu verbinden.
The Panel Link Frame was used during call setup to connect an idle Sender to the District selector requesting. When this connection was established the caller would hear dialtone. As the caller dialed a number the sender would call in a Decoder to obtain routing information and start setting up the connection while the caller was still dialing. At the completion of call setup the Sender would 'advance' the District selector into 'talk' position. At this point the Sender and Link are out of the call and the caller could hear the distant end.
A Link Frame could handle 100 Senders.
Link selector circuit failures were indicated by a minor alarm, aisle pilot and frame indicator lamp.
Panel offices had different sounding bells for minor alarms. This was accomplished by using different bells in the ringer boxes.#
Bildquelle: Public Domain