Couldn't find the model numbers on Philips or Magnavox websites, or any security cameras for that matter. Maybe they have that stuff on a different site, or it's not a USA product.
Camera + audio, needs 4 wires, so could be phone cable, Cat5 ethernet, or something similar. I'd see how many contacts are in the connector, if its 4, try a phone cord, 8 try a network cable (most likely). The cameras should get power from the monitor. Acquired, means might not work... Some people fail to mention that.
**broken link removed**
Is this the set up?