User manual

10
Communication to the keyboards is RS-485. Maximum cable distance for RS-485
communication over 24-gauge wire is 1.2 Km (App. 4000 feet). We recommend
using shielded twisted pairs cable that meets or exceeds the basic requirements
for EIA RS-485 applications.
 Junction Box’s input and output terminal
Plug the power supply, 12 VDC into suitable outlet on the rear of the junction box.
It is also supplied power to keyboard. It is included into keyboard package.
Use the data cable that is supplied with keyboard package. Plug one end of cable
into the RJ-45 connector on the rear of the keyboard and other end into the RJ-45
connector on the rear of the data junction box.
 “Exteriorly pull up” is?
Don’t put pull up resistance to collector of transistor and make ‘The line driver’ pull
up, then it can run function normally.
 Ascertain
The check voltage of GND and RTS should be over 5V.
 Caution
Sub keyboard can run function only in general control. Under the situation that
alarm is on in main keyboard, you can hear alarm sound when sensor actuated.
Data cable using for control of camera only connected to main junction box, can
make sub keyboard function.