Absar Naseer

51757648, Dec 29, 1992

Oct 18, 1990

7/599537

Lalit O. Patel - Mesa AZ
Michael Warner - Phoenix AZ
Absar Naseer - Mesa AZ

AG Communication Systems Corporation - Phoenix AZ

H04M 1900

379412

An enhanced high voltage line interface circuit for a digital switching system over which a connection is established between a digital switching system and a subscriber instrument via a subscriber loop. The high voltage line interface circuit includes in combination circuits that provide power to the subscriber loop and convert received analog voice signals transmitted from the subscriber instrument into differential voltage voice signals for subsequent conversion to digital data for use by the digital switching system. Additionally, differential voltage voice signals from the digital switching system are converted to analog voice signals for transmission along the subscriber loop to the subscriber instrument. The high voltage line interface circuit further includes circuits that detect and monitor the subscriber loop status and develop digital logic output signals that are used to report the status of the loop to a digital switching system controller.

53234600, Jun 21, 1994

Jan 7, 1992

7/817709

Michael Warner - Warrenton VA
Lalit O. Patel - Mesa AZ
Absar Naseer - Chandler AZ

AG Communication Systems Corporation - Phoenix AZ

H04M 1900

379399

An enhanced subscriber line interface circuit for a digital switching system which includes a line configuration and protection circuit connection tot he subscriber line and to a thick-film hybrid module. The thick-film hybrid module comprises a high voltage interface circuit and a PCM conversion circuit. The high voltage interface circuit provides power to the subscriber line, converts received analog voice signals transmitted from the subscriber instrument into differential voltage voice signals and detects the subscriber lines status. The PCM conversion circuit is connected to the high voltage interface circuit and is disposed to convert received differential voice signals into PCM digital signals. A line control interface circuit receives control signals from a peripheral processor of the digital switching system, controls the operation of the circuits of the thick-film hybrid module, and receives subscriber line information from the high voltage interface circuit which it passes on to the peripheral processor. A time slot assignment circuit connected to the peripheral processor is arranged to develop and transmit to the PCM conversion circuit time slot assignment information and to connect the PCM digital signals from the enhanced subscriber line interface circuit to the digital switching system.

53475755, Sep 13, 1994

Mar 26, 1992

7/857908

Absar Naseer - Chandler AZ
Lalit O. Patel - Mesa AZ
Edward M. Horiuchi - Glendale AZ

AG Communication Systems Corporation - Phoenix AZ

H04M 300

379377

A circuit for indicating the status of a telephone line at the CPE end, where the status is either on-hook, ringing, or off-hook is disclosed. The telephone line is the normal two-wire telephone line. First, a transconductance amplifier converts a floating voltage difference between the two-wire telephone line into a current. The current is proportional to the voltage difference. Next, a current to voltage converter converts the current from the transconductance amplifier to a single ended ground referenced voltage. The single ended voltage is proportional to the current from the transconductance amplifier, thus the single ended voltage is proportional to the voltage difference across the two-wire telephone line. A voltage controlled switch is turned ON when the single ended voltage is greater than a predefined value indicating the on-hook status. When the single ended voltage is below the predefined value, the voltage switch is turned OFF indicating the off-hook status.

52532917, Oct 12, 1993

Oct 18, 1990

7/599533

Absar Naseer - Mesa AZ
Michael Warner - Phoenix AZ
Lalit O. Patel - Mesa AZ

AG Communication Systems Corporation - Phoenix AZ

H04B 320

379406

A hybrid balance and combination codec filter circuit used in a subscriber line interface circuit over which a connection is established between a digital switching network and a subscriber instrument. The hybrid balance and combination codec filter circuit in combination includes a transmit section that converts differential voltage audio signals representing voice transmissions transmitted from the subscriber instrument into Pulse Code Modulated (PCM) encoded digital data, for transmission to the digital switching network. A receive section converts PCM encoded digital data representing voice signals switched through the digital switching network into differential voltage audio signals for transmission to the subscriber instrument. An included hybrid balance and echo cancellation section connected between the transmit section and the receive section reshapes the audio band signals output by the receive section. The reshaped audio band signals are applied to the transmit section, where they cancel any reflected audio band signals not completely transferred to the terminating impedance.