Please be more specific; exactly WHICH P1 system? There are several that the old 96 series can't handle, such as Phase 2 systems running as Phase 1 in the 700 Mhz band, or trunking in the 380 Mhz band for military?
We need to know which system. The PRO-96 and PRO-2096 do not load the band plan from the control channel. You need a custom band plan for a site with anything other than 800 MHz frequencies. It cannot trunk track 700 MHz frequencies.