[Sender frames, dial equipment.]

[District selector frame in a dial exchange.]

[General view of sender frames in a panel dial central office.]

[Telephone operators.]

[Telephone operators.]

[Overseas switchboard at 32 Avenue of the Americas.]

[Telephone operators.]

[Early types of switchboards.]

Communications, Telephone Exchange.

A Program of Lectures

Communications, Telephone Exchange.

Communications, Telephone Exchange.

Telephone, New York Telephone Co. Exchanges.

Communications, Telephone Exchange.

Telephone, New York Telephone Co. Exchanges.

[Early types of switchboards, Old Spring Exchange.]

Communications, Telephone Exchange.

Marconi, Wireless Telegraphing.

Marconi, Wireless Telegraphing Apparatus.

[Close up of a teletypewriter switchboard.]