I am hooking up a copuple of box camera in a retail store. They will be placed relatively near each other but here is my question.

1. I have siamese coax connected to the one camera(cam1) but want to know if there any way that i can connect another camera (cam2) to the same coax as the other camera(cam1 ) Please note is there any way that i would be able to view both cameras on a monitor in my office and switch between the 2 of them?

Hi, this may be what you are looking for.
http://www.cctvforum.com/viewtopic.php?p=75274

Though it may be cheaper just to run 2 cables and use a cheap electronic store AV switcher.

I have done that, just that I couldn't watch both cameras at the same time. I designed a system, whereby I ran one coax, and one 16/3 Belden power cable. My system switched the cameras ( one color, one black/white) via a photocell control, which the photocell switched an Ice Cube relay coil. I don't have this system at home, as I built them for friends who have large property out in the local foothills. Ended up building 5 of them for different property owners. All still working after 3 years now. Switch from color in the day, to b/w at night, via the $7 photocell control. all video and power runs on 1 coax, and 1- 16/3 power cable. Couldn't find one camera to do it, so ran 2 Sony SSC series with the Exview/Exwave. Not sure if you can wire it to watch both cameras at the same time, though.