Video Baluns come on two distinct groups: passive and active.

Passive baluns require no power to operate and work well up to about 500 metres.
Active baluns require power and can send video signals over 1Km down a low cost CAT5 cable.

Active Baluns

Send & receive 1 video signal over 1Km down CAT5 cable
con850/855 balun diagram
CON850 & CON855
Send & receive 1 x video, 1 x audio & data over 1km down CAT5 cable
con860/865 balun diagram
CON860 & CON865