Browse Prior Art Database

Modem Signal Path Control

IP.com Disclosure Number: IPCOM000116704D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Padgett, RS: AUTHOR [+3]

Abstract

Disclosed is a method for switching the analog path of a personal communicator between an Radio Frequency (RF) deck for cellular transmission and a wired path for transmission over the Public Telephone Network, as determined according to the way the device has been connected. The default condition, in which the device is not externally connected, allows cellular operation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 55% of the total text.

Modem Signal Path Control

      Disclosed is a method for switching the analog path of a
personal communicator between an Radio Frequency (RF) deck for
cellular transmission and a wired path for transmission over the
Public Telephone Network, as determined according to the way the
device has been connected.  The default condition, in which the
device is not externally connected, allows cellular operation.

      Fig. 1 is an isometric view of the personal communicator 10 in
an exploded relationship with the attachment devices allowing it to
communicate over the Public Telephone Network.  These devices consist
of an RJ11 cable 12 having a 33-pin connector 13 for attachment to
the personal communicator 10, a Data Access Arrangement (DAA) 14
allowing direct attachment of the RJ11 cable to the telephone system,
and a telephone cord 15 plugging into a standard telephone wall jack
16.

      Fig. 2 is a schematic view of a circuit within personal
communicator 10 for directing the analog signal path from a modem 17
to the RJ11 cable 12 over line 18 if this cable 12 is attached, or to
an RF deck over line 19 if the cable 12 is not attached.  The
connector 13 of RJ11 cable 12 includes three pins 20 which are each
hard wired to a ground line 21 to force an associated ID bit to a
"zero" level.  The lines 22 determining the three external ID bits
enter the circuit on pins from the RJ11 connector.  The Modem in Use
line 23 is driven active (low) by software running in t...