In 1982, the only manufacturer was Thomson SA; a successor company, ST Microelectronics continues to make the devices.
This type of crowbar protector is widely used for protecting telecom equipment from lightning-induced transients and induced currents from power lines.
Other manufacturers of this type of device include Bourns (TISP) and Littelfuse (SIDACtor).
In this case, the gate is connected to the telecom circuit power supply (via a diode or transistor) so that the device will crowbar if the transient exceeds the power supply voltage.
The main advantage of this configuration is that the protection voltage tracks the power supply, thus eliminating the problem of selecting a particular breakdown voltage for the protection circuit.