Data access arrangement utilizing a serialized digital data path across an isolation barrier

• US 6,359,973 B1
• Filed: 11/16/1998
• Issued: 03/19/2002
• Est. Priority Date: 11/16/1998
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Rahamim, Raphael, Beutler, Thomas Grey, Riggert, Eric Floyd
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US09/193,007
• Time in Patent Office: 1,219 Days
• Field of Search: 379/93.05, 379/93.28, 379/90.01, 379/93.31, 379/93.29, 375/222
• US Class Current: 379/93.05
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision

Abstract

A modem utilizing a DAA having line side circuitry including a telephone network interface and system side circuitry including a host system interface. The line side circuitry and the system side circuitry are separated by a high voltage isolation barrier. In accordance with the invention, the high voltage isolation barrier and other DAA circuitry are configured such that data and control information may be communicated between the system side circuitry and the line side circuitry using a serialized digital communication protocol. In one embodiment of the invention, the line side circuitry of the modem includes detection and measurement circuitry that is programmable to measure or establish electrical characteristics (e.g., tip/ring voltage and loop current) of the telephone line interface connection. Command information for the programmable circuitry is multiplexed with data communicated across the high voltage isolation barrier. Interrupt signals and information for synchronizing communications between the system side circuitry and the line side circuitry may also comprise a portion of the serialized datastream.

Claims

1. A data access arrangement, comprising:

a high voltage isolation barrier having a first side and a second side;

system side circuitry coupled to the first side of the high voltage isolation barrier, the system side circuitry configurable to communicate with host system circuitry;

line side circuitry coupled to the second side of the high voltage isolation barrier, the line side configurable to communicate across a telephone network;

wherein data and control information is communicated between the system side circuitry and the line side circuitry across the high voltage isolation barrier in a multiplexed, serialized digital datastream;

the high voltage isolation barrier comprises a first capacitor and a second capacitor;

the system side circuitry comprises a first transceiver circuit for bidirectional communications with the high voltage isolation barrier, and wherein the line side circuitry comprises a second transceiver circuit for bidirectional communications with the high voltage isolation barrier, the first and second transceiver circuits configured to transmit/receive differential signals across the first and second capacitors to communicate the multiplexed, serialized digital information; and

the high voltage isolation barrier further comprises circuitry configurable to provide a clock signal from the system side circuitry to the line side circuitry, and wherein the multiplexed, serialized digital information is communicated at approximately one half of the frequency of the clock signal.