[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.]

[People observing telephone operators.]

[Early types of switchboards.]

[Early types of switchboards, Old Spring Exchange.]

A Program of Lectures

Communications, Telephone Exchange.

Communications, Telephone Exchange.

Communications, Telephone Exchange.

Telephone, New York Telephone Co. Exchanges.

Telephone, New York Telephone Co. Exchanges.

Communications, Telephone Exchange.

Marconi, Wireless Telegraphing.

Communications, Telephone Exchange.

[Close up of a teletypewriter switchboard.]