Abstract: A circuit for resetting a computer upon detection of changes in the signals of an RS-232C communications port in the computer. The changes may indicate an incoming phone call or loss of a previously established communication link. The circuit may monitor the RING INDICATE (RI) signal of the RS-232C port to detect the former condition and either the DATA CARRIER DETECT (DCD) signal or the DATA SET READY (DSR) signal of the RS-232C port to detect the latter condition. A timer prevents spurious changes in the monitored signal from causing the computer to reset.

Abstract: A switching circuit places a load across the TIP and RING signals of a telephone line when the computer is reset and removes the load when the computer accesses a selected memory location. Thus, the telephone line remains in an off-hook state after the computer is reset and remains in that state until the computer executes software that causes the telephone line to return to the on-hook state. The computer may also execute software that causes the telephone line to enter the off-hook state.

Abstract: A remotely-activated telephone system for remote caller controlled communication with the disabled having a master unit connected to a telephone line and at least one satellite unit. The disclosed system provides channel means for bi-directional coupling of acoustic signals between the satellite unit and the telephone line through the master unit and control means responsive to a control signal received from a remote caller by way of the telephone line. The disclosed control means allow a remote caller to select a satellite unit and to establish two-way speech communications without intervention by the disabled party.