Browse Prior Art Database

SETTING A MODEM'S INITIAL AT STRING IN A DIGITAL RADIO NETWORK

IP.com Disclosure Number: IPCOM000007913D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-May-03
Document File: 2 page(s) / 81K

Publishing Venue

Motorola

Related People

Ed Benyukhis: AUTHOR [+3]

Abstract

In digital cellular systems such as iDEN, USDC, CDMA, GSM and JDC, PSTN modems can not be connected directly to the MS due to voice compres- sion in the network.

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M-LA Technical Developments

SETTING A MODEM'S INITIAL AT STRING IN A DIGITAL RADIO NETWORK

by Ed Benyukhis, Barry Chan and Rod Averbuch

PROBLEM DESCRIPTION:

  In digital cellular systems such as iDEN, USDC, CDMA, GSM and JDC, PSTN modems can not be connected directly to the MS due to voice compres- sion in the network.

  Therefore, a gateway (IWF) is implemented to gateway between the PSTN audio modems and the digital network.

  The MS specifies a call type to the switch and in a data call case, an IWF modem will be allocated towards the PSTN. Most of PSTN modem default time out value between phone pickup and remote modem tone is about 2-3 second. This is a very short time that forces the IWF to start modem negotia- tion immediately after dialing before the MS has a chance to generate initialization string to the IWF PSTN modem.

IWF

  In iDEN, modem rate and LAPM capability is negotiated in order to get the maximum available rate and LAPM flow control capability for binary and ASCII file transfer.

  In some old modems the negotiation pattern is interpreted as data. The wrong data causes the appli- cation to terminate the call.

  2. GSM solution does not enable any negotia- tion. GSM utilizes an expensive multi numbering scheme and XOFF/XON flow control. Using such flow control does not allow binary file transmission. iDEN modems negotiate LAPM and if existing, iDEN uses PSTN layer 2 protocol flow control, that enables the transmission ofany file type.

  3. In the current iDEN...