GE KTD-405, User Manual, Page: 12 / 76

KTD-405/KTD-405A Controller Keypad
User Manual
8
Installation guidelines
Plan your system’s camera and device assignments before installing the system. To help plan your system, use
the
System planning chart on page 69. And when installing your KTD-405 keypad, follow these guidelines:
• Each keypad requires its own I/O box. You can connect multiple I/O boxes to each other (using the
RS485 control signals) to establish multiple keypads for controlling one system. For systems that are
more complicated than are diagrammed in these instructions, contact GE Technical Support for
assistance. (See
Contacting technical support on page 55.)
• The audio and speaker connections are used only with a KTD-405A.
• Observe polarity when installing the RS-422 and RS-485 cables as well as the 12 VDC power supply
(if you are not using the provided transformer with positive polarity center plug).
• The keypad itself is not grounded.
• Grounding the I/O box is optional, but it does provide some additional protection against equipment
damage due to power surges caused by electrical storms.
• There must be no current in the shield of shielded cables. Maintain an open circuit (noncontinuous
path) for the shield and hold it at the earth ground potential by grounding it at only one location.
• You can connect the RS-485 shield of individual cable segments to each other, but to nothing else. You
will still ground the resulting shield circuit at one location only, despite the number of shield junctions.
• Each electrical circuit (RS-485 segment) must be biased. If keypads reside on separate electrical
circuits (separated by fiber or Ethernet bridges, for example), then more than one keypad might have
the bias switch set to ON (one for each circuit).
• The bias is sensitive to the polarity of the 12 VDC supply. If polarity on the power line is reversed, the
keypad will not be damaged, but biasing will not operate correctly.
• Each electrical segment being terminated must be terminated at each end with bias turned on at one
location only. Termination is generally required for the first and last device on a longer line. The
termination switches are located within or on the devices themselves (keypads and cameras). Refer to
the devices’ manuals for termination requirements and methods.
• An electrical segment for biasing and termination considerations may consist of several wire runs and
devices. For example, in
Figure 67 on page 61 there is only one electrical segment even though there
are several pieces of wire and several devices.
• Your system should contain only one RS-422 chain of devices. Only one KTD-405 keypad should be
in that chain, which can contain any number of other RS-422-only keypads such as KTD-404s.
Note: The keypads ship with an updated I/O box that provides RJ45 ports for the RS-485 data line and an RJ11 port for audio.
See
Connecting new and old I/O boxes on page 16 for connections between the new and old I/O boxes. For connection
details for the old I/O boxes, see Old I/O box connections on page 62.
Table 1. Recommended cable types
Signal Cable
1
1. Refer to the devices’ manuals for specific cabling requirements.
Minimum Size
RS-485 STP (shielded twisted-pair) 22 AWG
RS-422 UTP (unshielded twisted-pair) 22 AWG
Audio STP (shielded twisted-pair) 18 AWG