Revo REJCPTZ-2 - Manual (Page 6)

Part I
Introduction
■Introduction
■Function
■Application
Keyboard Introduction
This small keyboard provides joystick and keyboard control for one or many
connected PTZ cameras.
The keyboard can be used to control PTZ cameras or similar devices that use the
REVOTRAX, Pelco D or Pelco P protocols. (REVOTRAX is the default protocol.)
The keyboard’s multi-function joystick can control Pan, Tilt, Zoom, Focus, and Iris
adjustments. A twist function and a control (CTRL) button are included.
The keyboard has a built-in backlit LCD screen that displays pertinent information
for easy use.
Keyboard Function
The keyboard is used to control REVO PTZ cameras (using the REVOTRAX
protocol) or other PTZ cameras (using Pelco D or Pelco P protocols).
The default keyboard settings are REVOTRAX, 9600 baud rate, Camera ID= 1
The keyboard’s current set-up information will be displayed on the LCD screen
for two seconds immediately after each power-up.
The keyboard is equipped with one RS-485 communication port and supports
Part V Appendix
Appendix A RS485 Bus Basic Knowledge
Appendix B Technology Parameters
Appendix A: RS485 Bus Basic Knowledge
1. Characteristics of RS485 Bus
As specified, an RS485 bus allows half-duplex data transmission over a pair of wires
having a characteristic impedance of about 120 Ohms. The maximum load capacity is
32 unit loads (this includes the main controller and the controlled equipment).
2. Transmission distances of RS485 Bus
When 24AWG (0.56mm) twisted-pair wires are used as data transmission cable, the
maximum theoretical transmitting distances are as follows:
Baud Rate Transmission Distance (Max.)
2400bps 5,906ft(1800m)
4800bps 3,937ft(1200m)
9600bps 2,625ft(800m)
If the user selects thinner cables, or installs the units in an environment with strong
electromagnetic interference, or connects many devices to the RS485 Bus, the
maximum transmitting distance will be decreased. To increase the maximum
transmitting distance, do the contrary.
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