Installation Instructions
Model 117A4 Carrier Installation Instructions Understanding Carriers
Model 117A4 Carrier Installation Instructions 
503-801-18010 Issue 2  February 1999
General Positioning 
Rules
Failure to observe the following rules regarding location and use will result in poor 
performance of your MDW telephone.
•
Position the carrier(s) in a central location, relative to the handset(s) usage area, 
leaving at least 6 feet (1.8 m) between the carrier(s) and the communications 
system switch/control unit or other wired phones. If your switch/control unit is 
located in a remote location, you may have to run a telephone line cord from your 
switch/control unit to the centrally positioned radio module or carrier(s). The line 
cord maximum length is 1,000 feet (305 m) of 26-gauge cable.
•
The carrier(s) should be placed high on the wall for optimum voice quality and 
range. Allow 6–12 inches (15.2–30.5 cm) of space between the top of the antenna 
on the radio modules and the ceiling.
•
The carrier(s) should never be installed above a drop, suspended ceiling.
•
The carrier(s) should not be within 3 feet (.9 m) of any large metal object, and 
should not have metal objects in the line of sight to the operating area of the 
handset.
•
The carrier(s) should not be within 6 feet (1.8 m) of equipment with 
microprocessors such as answering machines, personal computers, and fax 
machines; control units, communications system switches, or other phones 
(especially speakerphones); competing radio devices such as wireless bar-
code scanners; electromagnetic equipment such as electric motors; or 
electrical main power feeds, junction boxes, circuit-breaker panels, fuse 
boxes, or 220-volt power lines.
•
The carrier(s) should not share the same power line as equipment with 
microprocessors such as answering machines, personal computers, and fax 
machines; or electromagnetic equipment such as electric motors.
•
If your communications system uses an uninterruptible power supply, such as a 
backup generator, you may want to connect the radio module or carrier(s) to that 
power supply.
POWER
RADIO
PASS
Radio 
Module
5 to 10 feet (1.5 to 3.1 m)
Signal Strength = 9 to 10
Voice Quality = 9 to 10
Close-Up Test
Signal Strength = 3
Voice Quality = 7 to 8
*At High Power—Power Level = 8
*Edge-of-Usable-Range Test










