Unwanted feed from camera

[golombek at adelphia.net]

At our school we're broadcasting morning announcements using two cameras 
and an eMac for canned video footage(interviews, etc,) and running through a 
RadioShack switchbox to change between cameras and eMac. When we switch 
to one digital video camera, a JVC, the "REC" logo appears through the unit 
and onto the tape. 
Does anyone know how we can get rid of it, especially without changing to 
another camera. Thanks!
Dennis

Remember our men and women serving our country.