Bosch CCTV distance dilemna

[Silicon Sam <siliconsam@xxxxxxxxx>]

  I have a local client that has a campus with 8 buildings.  Buildings
1 through 7 have all their CCTV piped over to building 1 via twisted
pair, and the Bosch Bi-Phase over 18ga shielded twisted pair.  All is
good with 6 of the buildings. (building 8 has a completely different
CCTV system)

  Building 7 however has a single 25 pair Cat3 cable running 4 twisted
pairs for cameras, TR560 and TT560 used for video, and a couple of
pairs for Bosch Bi-Phase control.  Video is weak and crappy, and
control is non-existant.  I measure about 400mv AC at the headend for
control, like 4mv while joystick is moving at the building 7.
Obviously this is not the right cable.  It was installed maybe 3-5
years ago, no one at the site has seen it work, so we don't know if it
ever did.  Cable run is approx 1500 feet.

  I have several options, I think, and wanted to see if anyone has any
others.

Try to triple, quad, or more up the 24 gauge wires on the control,
since we have so many spares.  Hadn't tried that yet, but video sucks
anyways.

Go with a fiber link between the buildings.  The LTC 4628 and 4629 are
quite pricy however.

Go with some sort of Ethernet converter for this 1 building. Keep in
mind 4 cameras, 2 are PTZ Autodomes.

Add a small Bosch DVR at building 7, and monitor it at building 1

I had thought of running the video and control over to building 8, but
it has AD cameras and a March DVR, and I don't think the DVR over in 8
can handle the AD and Bosch Autodomes using 2 different protocols for
control.