I found one Experts Exchange post asking that same question, the guy said Inetcam did send it to him originally, but he lost it. The accepted solution was his own comment, stating he had to go by trial and error, but there was no contact information for this user. So unless you can get it from Inetcam again, it's not looking good.
I personally am thinking that it is similar to X10's X-Cam (which uses 4 wires with an RJ-25 jack I believe), where each video signal uses a shared ground.