They were assigned in New York to travel to France to operate telephone switch boards at the war front in Paris, and at Chaumont, Haute-Marne.

They also operated the telephone switch boards at First Army headquarters at Ligny-en-Barrois, about 5 miles (8.0 km) to the south of Saint-Mihiel, and later during the Meuse-Argonne Offensive.

[1] Banker sailed with her team members from New Jersey on 6 March 1918, to take up the assignment as chief operator for First Army headquarters in Paris.

Five months later, Banker was asked to move to the war front, to the First Army headquarters at Ligny-en-Barrois, south of Saint-Mihiel.

Equipped with gas masks and helmets, the women operated from trenches where the danger was real; despite this, those not chosen to go felt left out.

When the First Army headquarters moved to Bar-le-Duc in September, Banker and her operators had to work in a place which was damaged extensively.

As she did not find this job exciting compared to the work at the war front, she accepted an offer to move to the Army of Occupation at Coblenz, Germany; while there she was awarded the Distinguished Service Medal.

Reminiscing about her wartime experience as chief operator, Banker humorously noted that "an afternoon in the switchboard office sometimes sounded like a scene from Alice in Wonderland, where only the initiated can make sense of the proceedings".

[5] She also noted the confidentiality aspect of her assignment when she was tested by an intelligence officer about her ability to keep a secret, which was about her posting out of the unit.