Wireless modem

• US 20040171348A1
• Filed: 11/26/2003
• Published: 09/02/2004
• Est. Priority Date: 09/08/2000
• Status: Active Grant

• Current Assignee: NEBO Wireless LLC
• Original Assignee: NEBO Wireless LLC
• Inventors: Lin, Ernie, Giger, Adolf J.
• Granted Patent: US 7,409,195 B2
• Time in Patent Office: Days
• US Class Current: 455/39
• CPC Class Codes: H04M 1/738 Interface circuits for coupling substations to external telephone lines H04M1/78 takes precedence

Abstract

A modem includes a base unit for transmitting a data signal, and a communication card which receives the data signal from the base unit over a wireless medium and which performs echo canceling on the data signal. The base unit is in communication with a telephone line and receives an original signal from the telephone line. The base unit generates an RF modulated signal based on the original signal. The base unit includes a transmitter for transmitting the data signal. Circuitry in the base unit receives the original signal from the telephone line and generates a combined data signal from the original signal and echo signals and maintains a peak voltage of the combined signal which is within the linear amplification region of the transmitter.

Claims

1. A modem comprising:

base unit for transmitting a data signal; and

a communication card which receives the data signal from the base unit over a wireless medium, and which performs echo canceling on the data signal.

2. The modem of claim 1, wherein the base unit is in communication with a telephone line and receives an original signal from the telephone line, the base unit generating an RF modulated data signal based on the original signal.

3. The modem of claim 2, wherein the base unit comprises:

a transmitter for transmitting the data signal; and

circuitry which receives the original signal from the telephone line and which generates a composite data signal from the original signal and echo signals, and which maintains a peak voltage excursion of the composite data signal within a linear amplification region of the transmitter.

4. The modem of claim 3, wherein the circuitry comprises an automatic gain control circuit.

5. The circuitry of claim 4, wherein the automatic gain control circuit uses a dial tone of a telephone connection or a DC current of a telephone loop to set a gain level for the original signal at a beginning of communication, the gain level remaining substantially constant during communication.

6. The modem of claim 1, wherein the data signal is transmitted using multi-level frequency shift keying (FSK) modulation.

7. The modem of claim 1, wherein the communication card is in communication with the base unit and a computer, the communication card receiving an original signal from the computer, generating an RF modulated signal based on the original signal from the computer, and transmitting the RF modulated signal to the base unit.

8. The modem of claim 7, wherein the communication card includes an RF transmitter and an RF receiver, the communication card establishing wireless communication with the base unit, the communication card communicating with the base unit by wireless communication via an RF transmitter and RF receiver, the communication card communicating with the computer via a wired link.

9. The modem of claim 7, wherein the communication card includes a ringer emulator;

and

wherein a low frequency signal generator is used to emulate ringer detection circuits when a ringing signal is detected in the base unit and transmitted over the wireless medium to the communication card, the ringer emulator emulating ringer detection in a telephone interface and feeding a signal to a modem circuit to receive of incoming call.

10. The modem of claim 7, wherein the communication card includes a switch for selecting a type of medium over which to transmit and receive the data signal.

11. A modem comprising:

a base unit; and

a communication card for transmitting data signals to, and receiving data signals from the base unit, the communication card including a switch for selecting a type of medium over which to transmit and receive the data signals.

12. The modem of claim 11, wherein the type of medium comprises a wired medium.

13. The modem of claim 11, wherein the type of medium comprises a wireless medium.

14. The modem of claim 11, further comprising circuitry which triggers the switch in response to detecting a wired medium interface to the modem.

15. The modem of claim 14, wherein the circuitry comprises a line presence indicator;

and

wherein the switch is triggered to operate the modem in wired mode when the line presence indicator detects the wired medium and the switch is triggered to operate the modem in wireless mode when the line presence indicator does not detect the wired medium.