Apparatus and method for supporting analog fax calls in a tandem configuration

• US 20010040702A1
• Filed: 07/06/2001
• Published: 11/15/2001
• Est. Priority Date: 08/29/1997
• Status: Active Grant

• Current Assignee: Nikolai K.N. Leung
• Original Assignee: Nikolai K.N. Leung
• Inventors: Leung, Nikolai K.N.
• Granted Patent: US 6,819,454 B2
• Time in Patent Office: Days
• US Class Current: 358/434
• CPC Class Codes: H04N 1/00281 with a telecommunication apparatus, e.g. a switched network of teleprinters for the distribution of text-based information, a selective call terminal details of transmission H04N1/00095; establishing a communication with one of a facsimile machine or another apparatus sharing a single line H04N1/32704; interfacing cordless telephone terminals with an accessory to increase the functionality of user interface H04M1/72409
• CPC Class Codes: H04N 1/32797 Systems adapted to communicate over more than one channel, e.g. via ISDN changing transmission mode according to type of channel H04N2201/33364; multichannel or multilink communication protocols H04L69/14
• CPC Class Codes: H04N 2201/0015 Control of image communication with the connected apparatus, e.g. signalling capability
• CPC Class Codes: H04N 2201/3335 Speed or rate
• CPC Class Codes: H04N 2201/33364 Type of modulation; Type of channel, e.g. digital or analog; Type of communication, e.g. half-duplex or full-duplex
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices

Abstract

Apparatus and methods for supporting analog fax calls between two wireless subscriber stations in a tandem configuration are presented herein. To support the tandem configuration, full duplex communication may be established between the two base stations. Full duplex communication may be realized by incorporating an echo canceler in the base station, or by utilizing both BFSK channels of the V.21 fax system for communication. The tandem configuration may also be supported by advanced flag synchronization, wherein a second base station will immediately start sending preamble flags to a first base station after a message is transmitted from the first base station to the second base station. The first base station may then synchronize its receiver for immediate receipt of the return message from the second base station.

Claims

1. An apparatus for establishing a more efficient communication exchange between a first Group 3 device and a second Group 3 device over a wireless communication system, comprising a digital signal processor configured to determine whether a tandem condition exists between the first Group 3 device and the second Group 3 device and to establish a full duplex communication session between the first Group 3 device and the second Group 3 device if the tandem condition exists.