Good morning F/V Maizey James,
Thank you for your inquiry. To connect the GP33 to a 1935 radar it will require (2) cables. The GP33 uses a 10Pin connector cable and the 1935 uses a 7 pin cable. The part numbers for those cables are:
GP33 10 Pin Cable: 001-112-970
1935 7 Pin Cable: 000-154-028
Then it is just a matter of wiring the TX wires from the GP33 to the RX wires on the 1935.
GP33 wires: White and Blue
1935 wires: Yellow and Green
This is usually done on a small terminal strip with ring connectors. White would connect to Yellow and Blue would connect to Green.
Kind Regards,
C-Bass