I don't think it was ever "hooked up" to
any thing. Just used for copying
cards to disk and then feed the disk else where.
The IBM Magnetic Tape Selectric Typewriter was a STAND-ALONE
word processing machine, often used for creating form letters.
"Dear Mr. COLLEGE, of all the families on CAMPUS DRIVE, you
have been selected . . . "
It was usually called "MTST", pronounced "empty ST", which
gave rise to a TRS80 word processing program, (NOT from IBM)
pretentiously named "FULL ST"
Later, there was a Magnetic CARD Selectric Typewriter,
and even some ancillary machines.