SRX3600 does not have E1 PIC option. I am not aware of anything on the roadmap for T1/E1 on SRX3x00. SRX Branch (210, 240, 650) platforms have T1/E1 mPIM and gPIM options. To be honest, T1/E1 makes sense on SRX Branch devices which are intended for small to medium branch offices. It makes much less sense on SRX3000 and up which is designed more for the corporate office, carriers and datacenters.