Browse Prior Art Database

Service Junctor with Switchable Gain

IP.com Disclosure Number: IPCOM000075313D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Morlec, E: AUTHOR

Abstract

The telephone switching network represented schematically in Fig. 1 essentially comprises a Main Network MN and a Service Network SN. Network MN permits extension-to-extension or extension-to-trunk connections to be established, thru a Network Junctor such as MNJ. Network SN permits extensions or trunks to be connected to a service circuit such as an operator set OP or a tone generator, thru a Service Junctor such as SJ.

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Service Junctor with Switchable Gain

The telephone switching network represented schematically in Fig. 1 essentially comprises a Main Network MN and a Service Network SN. Network MN permits extension-to-extension or extension-to-trunk connections to be established, thru a Network Junctor such as MNJ. Network SN permits extensions or trunks to be connected to a service circuit such as an operator set OP or a tone generator, thru a Service Junctor such as SJ.

The Service Junctor circuit represented on Fig. 2 compensates the serial losses in a connection between the Main and the Service Networks. Moreover in the offer mode, i.e. when an operator wants to make a private offer to an extension E being connected to a trunk T, this junctor can be switched into such a configuration that the interference on the established call is minimized.

In a normal connection between an operator and a Main Network terminal, only Command C1 is applied. Junctor SJ acts as a repeater and presents a negative resistance RN = 2RE - (2 alpha - 1)R, which compensates for the positive resistance involved in the connection.

In the offer mode, command C1 is maintained and command C2 is now applied. Junctor SJ now presents a positive resistance RP=2RE-(2 alpha-1)Req in which Req = R.r/R+r.

As, in addition, Junction MNJ normally presents a negative resistance, the intrusion tone has a substantially higher amplitude on the extension side than on the trunk side. This reduces the interference with th...