I've acquired a couple of interesting early documents on the Army's FGC-30 tape relay center.

http://www.navy-radio.com/tty-relay.htm#army

One is a 1953 proposal to the Chief Signal Officer - it includes a photo of the experimental GGC-2 system installed at Fifth Army in Chicago

Another is a 1956 system description and includes photos of the FGC-30 prototype installed at Sixth Army in Davis.

Nick England K4NYW
www.navy-radio.com