124

The Tektronix Type 124 Television Adapter is a TV sync separator allowing a general-purpose oscilloscope to be triggered on a specific TV field/line.

Tektronix 124
Television Adapter Type 124 description in 1957 catalog Produced from (?) to (?) Manuals Tektronix 124 Manual 070-249.pdf needed, please add Media:Tek 124 history parts list.pdf (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

It also contains a time marker generator that can produce a marker highlight on the trace via the scope's Z input.