Browse Prior Art Database

Enable Connectivity of ISDN Co-Processor with 7820

IP.com Disclosure Number: IPCOM000108593D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Price, S: AUTHOR [+3]

Abstract

Described is a solution to the problem of ATT implementation of ISDN not supporting sub-addressing. By means of the method disclosed an ISDN Co-Processor Support Program can now support connections to an IBM 7820 Terminal Adapter.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Enable Connectivity of ISDN Co-Processor with 7820

       Described is a solution to the problem of ATT
implementation of ISDN not supporting sub-addressing.  By means of
the method disclosed an ISDN Co-Processor Support Program can now
support connections to an IBM 7820 Terminal Adapter.

      Because the 5ESS switch at software level 5E4 generic does not
support Calling Party Sub-Address (CPSA) or Multi-Subscriber Number
(MSN) or Direct Dialling In (DDI), the IBM 7820 Terminal Adapter
implements Port selection using Low Layer Compatibility.  IBM ISDN
Co- processor Support Program does not support LLC and thus any call
made to an IBM 7820 is connected to the maintenance channel (Port 0).
The two devices cannot communicate in this mode.  In order for
communication to be enabled, the call needs to be assigned to Port 1
(R-interface 1) or Port 2 (R-interface 2) of the IBM 7820.

      On networks, such as VN2 or BTNR191, CPSA is used to accomplish
Port selection and the administrators of each end of the connection
negotiate and decide which CPSA value will be assigned to which 7820
Port.  This CPSA value is then configured into the devices.

      On the 5ESS network, none of these facilities (MSN, DDI or
CPSA) is available and 7820 has implemented Port selection using LLC
in the following manner with strict Port assignment rules in which
there is no administrator negotiation or decision:
Port 0 : No LLC on the incoming call SETUP.
         This is configured into the 7820 as a Format 2 ISDN Call
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