Convert CCTV to Digital

[anthony.clendenen@xxxxxxxxx]

Hello,
I have a question about converting CCTV to a digital signal.  The
current setup is four cameras that connect to a multiplexer and then to
a VCR in the store (downstairs).  It is also connected to two monitors
that display the four camreas on the same screen, one in the store the
other in the office upstairs.  I would like to convert this to a
digital signal and have the images go to a computer hard drive in the
upstairs office.  Is is possible to take the BNC connection coming to
the monitor in the office upstairs and connect it to a DVR card and
record all foru camera outputs from the single cable?  If not what
would be the options.

TIA.

Regards.