We had a 10M unit attached to our machine back in 1964. It weighed in at just over 3/4 ton. 49 heads arranged along the drum matched the 49-bit machine it hooked to. The 49th bit was a parity bit.
We scrapped that after a year and went with a Burroughs D82 with a D825 Front end to handle 36 incoming and 24 outgoing TTY channels. All our programming was with punched cards.
Fun times.
Bill