wingfooted

thanks for the suggestion - tried, no joy. reversed, no joy.

FRUSTRATED AND TRYING EXPERIENCE ! I have a 8 ch Chinese DVR (Zmodo) that I am trying to interface with a a single (quantity one) Canon Vc-C50iR. There are two wires on the back of the Zmodo that read RS485+ and RS485-. These are the wires that take care of the Pelco D transmission to the Canon. I get 3.2 volts on the RS 485+ wire and if I operate the PTZ control on the Zmodo DVR the DC voltage drops a small amount -to maybe 3.15V. On the Canon I have a plug that allows access to pins A1 - A10 and B1 - B10. These are the pins that control the Canon. From the Canon manual, figured that I just needed to connect RS485+ to the Canon pin B7 RXD input receive data and RS485- to Canon pin A7 TXD input send data. This does not operate the Canon PTZ camera. The camera operates normally in PTZ mode with the remote control. So the camera is working - just not with the Zmodo DVR. Each unit is set up for Pelco D protocol, 9600 BAUD, correct stop bits, ect. With nothing connected I have +10V on pin A6 - RTS send data request and -10V on pin A7 on the camera end if that is any help. Any suggestions how to hook up the Canon to the DVR are highly welcome and appreciated.