One option on the first TCAS installations used a pair of RA-TA-VSI which display both traffic and RA red-green arcs on a CRT or LCD VSI.
Another option was a pair of RA-VSI which were just electro-mechanical VSI with a ring of red/green LED added to the perimeter. The traffic display was usually the WX radar indicator.
When Boeing upgraded the EFIS symbol generators on the 75/76/73, they provided both RA advisory on the EADI and traffic display on the EHSI. I haven't heard of a plane with RA advisories on the ADI, and traffic on the VSI.
Back then, TCAS was on a 10 day MEL.
GB