User's Manual

TY91/TY92 VHF Radio Installation Manual 11 April 2012
00839-00 Issue AA
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Trig Avionics Limited 25
5.8.6 Transfer Button
The transfer button is used to allow remote activation of the frequency change,
and is typically used in a helicopter. The input is active low, and will be
asserted when the voltage to ground is pulled below approximately 4 volts.
5.9 D Connector Crimp Terminals
The 25 way and 15 way connectors supplied with the TY91/TY92 installation
kit are MIL standard versions of the popular sub miniature D type connector
family, and use individual crimp terminals and a receptacle. The MIL
specification for this family of connectors is MIL-C-24308. We supply crimp
terminals because these are more reliable than soldered connections, and are
easier to assemble in-situ in an aircraft, where soldering is impractical. They
also allow individual wires to be removed and replaced in a receptacle without
replacing the whole connector.
The socket contacts used in the connectors conform to MIL part number
M39029/63-368, and are also suitable for wire gauges from 20 to 24 AWG.
These contacts are widely used in avionics installation, and there are many
tools available on the market that will reliably crimp them to the wiring.
Because the contacts are a MIL standard, there is also a MIL standard for the
crimp tool, although other proprietary solutions are also available.
The MIL reference for the basic style of hand tool is M22520/2-01. This style
of tool can crimp many different contact types, and relies on interchangeable
"positioners" to hold the actual contact in use. The MIL reference for the
positioner that you need for the crimps we supply is M22520/2-08.
Any tool that complies with these references can be used to crimp these
contacts. One of the most popular vendors of these small hand tools is Daniels
Manufacturing Corporation (see www.dmctools.com). Their AFM8 hand tool
complies with M22520/2-01, and their K13-1 positioner is M22520/2-08
compliant, so the combination will crimp the supplied connectors.
Once crimped, the contacts should be slotted into the rear of the connector
shell. Push the contact in until the retaining tab clicks into place. Tug gently
to confirm the contact is locked in place.