Northern Airborne Technology PTA12-1xx - Manual (Page 11)

PTA12-100 POTS Telephone Adapter with Display
SM55-2 Installation and Operation Manual
Section 2 Rev: 1.01
Issue 4 Page 2-2
ENG-FORM: 805-0121.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4 Installation Procedures
2.4.1 Warnings
WARNING:
High volume settings can cause hearing damage.
Set the headset volume control to the minimum volume setting prior to conducting
tests, and slowly increase the headset volume to a comfortable listening level.
2.4.2 Cautions
CAUTION:
Do not take a ground from the instrument panel or similar location that shares a ground
return with a turn and bank, horizon or other motor driven instrument. This may cause the
PTA12-100 unit to pick up the sound of the motor as ground loop interference..
2.4.3 Cabling and Wiring
All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to
MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.
For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the connector map in
Section 2.7 as required.
Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Reference the interconnect drawing in Section 2.7 for shield termination details.
Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions.
Unless otherwise noted, all wiring shall be a minimum of 22 AWG, except power and ground lines, which
shall be a minimum of 20 AWG. Reference the Interconnect drawing for additional specifications. Check
that the ground connection is clean and well secured, and that it shares no path with any electrically noisy
aircraft accessories such as blowers, turn and bank instruments or similar loads.
2.4.4 Post-Installation Checks
2.4.4.1 Voltage/Resistance Checks
Do not attach the PTA12-100 until the following conditions are met.
Check the following:
a) Check P101, pins <1> and <3> for +28 Vdc relative to ground.
b) Check P101, pins <14>, <16> and <19> for continuity to ground (less than 0.5
Ω).