Stores Ref. No.:10L/9563379
Nato Stock No.:5895-99-956-3379
Attachment:Dzus D5 Panel Line quarter turn fasteners
Connection:602 pattern, 55 way
Installation:A.R.I. 23134/3


The control unit interfaces directly to the transponder unit of the Mk10 IFF (Indication Friend or Foe) / SSR (Secondary Surveillance Radar) system, otherwise known as IFF/SSR 1520.

The purpose of this system is to reply to radar interrogation with a coded number, which identifies the aircraft to the radar operator.

I.F.F/S.S.R. Transponder Control Unit

Inside unit: switches and lashed wiring harness.


Simulation is anticipated to be straightforward as the control units switches all control individual ways of the connector. IFF is modelled within flightgear, aiding multi-player scenarios and air traffic control.


As mentioned above, having the right connector for this unit would make interfacing a lot easier.

The fixed plug on the chassis is a "602 pattern" connector (MIL-C-26482). The contact layout has 55 contacts (size 20).

I.F.F/S.S.R. Transponder Control Unit - 22-55P Connector

Connector needed for interfacing.

It is marked as an 22-55P; the 22 being 22 16ths of an inch in diameter, and the 55 is the contact count, the P means Pins (instead of S for Socket), no further identification letters indicates a normal orientation.

So, I am after a mating free socket, which would be marked 22-55S, of standard orientation.


T Mk.5 electrical "Vol. 1":
A.P.101B-1005-1B, Sect. 9, Chap. 2, A.L.59 Sept. 1973, I.F.F/S.S.R. 1520 - Paragraph 4

T Mk. 5 wiring diagrams:
AP101B-1005-10, Sheet 36, A.L.3, Nov 1981, Cabin Lighting, Port
AP101B-1005-10, Sheet 57, A.L.6, Jan 1985, Radio and Radar Installations - Fig 3, I.F.F./S.S.R. 1520