Hi everyone, Im glad to have found this forum! My problem is I recently had to replaced a dvr which got stolen, with a new one. On the old dvr I had a PTZ setup and it worked great, the issue is the old DVR had a plug with 4 wires for the rs 485 and the new dvr has only 2? Now I only have 2 wires running to ptz camera but on the old DVR I had 2 jumpers right at plug going Im assuming from rx+ to Tx+ and rc- to tc-, now the new dvr only has 2 terminals marked + and - and when I connect my 2 wires running from ptz device up to the new dvr I cant get it to communicate? the only difference being old dvr had 4 wire hookup with jumper and new one only has two? Im really stumped at this point? Thanks in advance.