Help with Smoke Detector Wiring

Hi, Need help with Honeywell Vista-20P Home Alarm System Smoke Detector wiring we are going to replace 2 old System Sensor 2100T we were told by System Sensor that we should use 2WT-B 2-wire Photoelectric i3 Smoke Detector with a 135F Fixed Thermal Sensor, are 2100T smoke detector we notice one they 4 wires it looks like they have them wired in parallel we are not sure how the new use 2WT-B 2 should be wired we have 2 black and 2 red wires



Here is a photo of are old 2100T



Thanks

Help with Smoke Detector Wiring