1934 Ash Tray Radio

[My3window]

Clarification please: I've seen photos of several radios speaker boxes, both ash tray and glove box types. On some I've seen what looks like an exterior switch on the upper left side of the speaker box. On others, there has been no switch at all. Can any one tell me if the switch I'm seeing is on both ash tray and glove box radios or just glove box types?

What was the function of the switch?

Thank you