Interservice I/S4 socket interface

Interservice I/S4 combines 2 side contacts and 2 lower contacts, giving 4 mating surfaces in this construction. Contact positions are essential to identification.

Interservice base drawings distinguish the versions within the series. Equal total contact counts do not automatically make two versions the same base: layout and locating references must also match.

Interservice must therefore be qualified by its construction number. Side contacts must not conventionally be relocated to the bottom, and electrical functions remain those of the valve shown.

I/S4 uses two short lower pins and two opposite round side connections. It differs from I/S2, which uses side plates. Four contacts in total do not eliminate the difference in mating-surface shape.

This construction belongs to Interservice development for compact valves with reduced inter-electrode capacitance. Verified metric dimensions for I/S4 are unavailable here. I/S1 plate dimensions are not transferred to round contacts.