Open the connector by removing the screws on its sides. Depending on the manufacturer, there may be one screw or more. With the screws removed, the two halves of the connector will separate and reveal the terminal connectors inside. Take care not to lose the short piece of plastic tubing found inside the body of the connector.
Strip three to five centimeters of outer insulation from the cable to reveal the metallic shield inside. Peel the shield back to the edge of the insulation, revealing the wires inside. Depending on the intended use for the cable, there will be a different number of wires. Speaker and microphone cables generally have two; branded DMX cables may have up to five.
Twist the shield into a single strand resembling a wire. This will act as the ground connection, helping to reduce interference.
Plug in the soldering iron and allow it to heat up. Feed the cable through the bottom portion of the connector so all of the stripped section is inside. Slide the length of plastic tubing over the loose wires. It will hold them together and prevent them from touching any metal surfaces inside the connector.
Hold the twisted shield to the first pin on the connector. Touch it with the hot soldering iron and apply three to four millimeters of solder. Allow the solder to cool and make certain the joint is solid. Solder one of the wires to the second pin on the connector. It doesn't matter which wire goes to which pin, provided that both connectors are the same at either end of the cable. Make a note of which color was attached to which pin. Repeat with all the wires in the cable, refit the other portion of the connector and replace the screws.