>The solution? Develop a radio system that the infantry and tanks
>could use to talk directly to each other? Noooo, of course not, that
>would have been far too complicated and taken too long, and there's
>probably some kind of rule about any military communications system
>interoperating that obviously.

Don't forget one other important thing at the time: Radios were not general issue, most of the infantrymen wouldn't even have one.

Adding an external access for the intercom system meant that anyone stuck on foot could talk to the tank crew, not just the one guy in the squad with a radio.