Well asume you 120 agents are ready for a call, so in first instance a first dialing request for all of them and assuming everybody answered on the other side you’ll need to detect 120 customer voices. Now on predictive you user an overdial (Agent Busy factor at 80% for example, which means you will have more dials than agents you have, so you’ll need to detect more signals).
From Genesys directly:
Normally, for predictive dialer we would recommend about 1.5 times the CPD ports for Agents. Meaning 100 Agent requires about 150 CPD ports
They even go higger…
We use 1.3 for a reasonable factors and assuming that it’s very hard to get that number of calls at once.