Connect the audio/video outputs on one recorder to the audio/video inputs on the second. This will be shown in the instruction manuals for the recorders. If you don't have the manuals, check if the manufacturer's website provides downloadable copies of the manuals, usually found under "Support". The manuals are usually in PDF format. The two-channel audio signal, L and R channels, are carried by shielded audio cables with RCA plugs on each end. The right channel is coloured red by convention: R(ight) = R(ed). You may be able to use a digital audio connection between the two devices, if one has a digital output and the other a digital input. Both recorders need to use the same type of connection, coaxial wire (RCA plugs) or optical (Toslink), or you will need to purchase a suitable digital signal converter (coax-to-optical or optical-to-coax). Video signals are carried over composite video, s-video, and/or component video lines. - Component video, best quality: three coaxial cables (Y,Pr,Pb) with RCA plugs on each end. - S-video, medium quality: a single twin-coaxial cable (Y,C) with 4-pin DIN connectors on each end. - Composite video, lowest quality: a single coaxial cable with an RCA plug on each end. Always use the best quality method of transmission. Cable quality does make a difference, regardless of what some people say, so don't use the cheapest cables you can find. A decent set of cables will run about US$100 and up, depending on the type of connection and the length of the cables. A set of three component video cables will cost two to three times as much as a single composite video cable. If both recorders are very new, they may provide HDMI digital input and output connections. If such is the case, use HDMI.