Browse Prior Art Database

Interconnection Unit

IP.com Disclosure Number: IPCOM000091015D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Jumper, F: AUTHOR

Abstract

Interconnection unit 1 is attached to standard telephone key equipment 2 for connecting a privately-owned PABX to the switching network of a common carrier. An incoming call from the common carrier switching network is sensed by the signal detector and control circuit 3. Current, passed from the network through circuit 3, closes contacts C-1 and causes an alert signal to be sent over wires 4 to a privately-owned trunk signal circuit which signals an attendant. When the attendant answers, contacts associated with the service request circuit close. This completes the circuit of relay A through diode D2 and of relay T through diode D1 over wires 5. Contacts A-1 and T-1 are thus closed, connecting the call to the PABX via repeating coil 6. The latter also serves to isolate the key equipment battery and the T relay battery.

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Interconnection Unit

Interconnection unit 1 is attached to standard telephone key equipment 2 for connecting a privately-owned PABX to the switching network of a common carrier. An incoming call from the common carrier switching network is sensed by the signal detector and control circuit 3. Current, passed from the network through circuit 3, closes contacts C-1 and causes an alert signal to be sent over wires 4 to a privately-owned trunk signal circuit which signals an attendant. When the attendant answers, contacts associated with the service request circuit close. This completes the circuit of relay A through diode D2 and of relay T through diode D1 over wires 5. Contacts A-1 and T-1 are thus closed, connecting the call to the PABX via repeating coil 6. The latter also serves to isolate the key equipment battery and the T relay battery. To complete an outgoing call from the PABX to the switching network, the attendant depresses push button 7 which is associated with a multiline telephone set. This connects the dial of such set over wires 8 to the switching network through contacts 11 and 12 of push button 7. Relay T is also disabled through contact 13, opening the voice circuit between the switching network and the PABX. The A-1 contacts remain closed. After the attendant dials the call, push button 7 is released which causes relay T to operate again, closing the talking path between the PABX and the switching network. Resistor R1 is a current limiting resisto...