Digital Monitoring Products Inc PC0137 User Manual

Several factors determine the performance characteristics of the DMP Keypad bus: the length of wire used, the 

number of devices connected, and the voltage at each device.  When planning an installation, keep in mind the 

following four specifications:

1. DMP recommends using 18 or 22-gauge 

unshielded wire for all keypad circuits.  Do not use twisted pair or 

shielded wire for keypad bus data circuits.  All 22-gauge wire must be connected to a power-limited circuit and 

jacket wrapped.

2. On keypad bus circuits, to maintain auxiliary power integrity when using 22-gauge wire do not exceed 500 feet.  

When using 18-gauge wire do not exceed 1,000 feet.  To increase the wire length or to add devices, install an 

additional power supply that is listed for Fire Protective Signaling, power limited, and regulated  

(12 VDC nominal) with battery backup.  

Note:  Each panel allows a specific number of supervised keypads.  Add additional keypads in the unsupervised 

mode.  Refer to the panel installation guide for the specific number of supervised keypads allowed. 

3. Maximum distance for any one bus circuit (length of wire) is 2,500 feet regardless of the wire gauge.  This 

distance can be in the form of one long wire run or multiple branches with all wiring totaling no more than 

2,500 feet.  As wire distance from the panel increases, DC voltage on the wire decreases.  

4. Maximum voltage drop between the panel (or auxiliary power supply) and any device is 2.0 VDC.  If the voltage 

at any device is less than the required level, add an auxiliary power supply to the circuit.  When voltage is too 

low, the devices cannot operate properly.  

For additional information refer to the panel installation guide and Keypad Bus Wiring Application Note (LT-2031).

If any Z-Wave devices do not operate, refer to the following checklist:

•  Verify equipment model numbers.
•  Verify the 

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:  

(1) This device may not cause harmful interference, and  

(2) this device must accept any interference received, including interference that may cause undesired operation.
Changes or modifications made by the user and not expressly approved by the party responsible for compliance could void the 

user’s authority to operate the equipment.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of 

the FCC Rules.  These limits are designed to provide reasonable protection against harmful interference in a residential 

installation.  This equipment generates, uses and can radiate radio frequency energy and, if not installed and used 

in accordance with the instructions, may cause harmful interference to radio communications.  However, there is no 

guarantee that interference will not occur in a particular installation.  If this equipment does cause harmful interference to 

radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try 

to correct the interference by one or more of the following measures:

-  Reorient or relocate the receiving antenna.

-  Increase the separation between the equipment and receiver.

-  Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

-  Consult the dealer or an experienced radio/TV technician for help.

Note: The 738Z Module is a two-way supervised wireless design.  It is compliant with FCC rules as they pertain to 900 MHz Spread 

Spectrum devices.  In rare instances it has been observed that certain 900 MHz cordless telephones may occasionally experience 

a clicking sound on the telephone while in use.  If this occurs, it may be resolved by selecting a different channel on the cordless 

telephone, or replacing the cordless phone with a different brand or model of 900 MHz telephone or other cordless telephone.
To comply with RF exposure requirements, a minimum distance of 20cm must be maintained between the antenna and all persons.

This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to the following two 

conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference 

that may cause undesired operation of the device.