This is Q-Bus magtape controller:
TC13: Emulex Pertec-interface tape drive controller. Switchable TU81
TMSCP (MU:) or TS-11 (MS:) emulation.
Nope, a TC13 is MS:-only. I think you're confusing it with the QT13,
which is switchable between TMSCP and TS11.
Tim.