Communications Audio Interface for Remote Operations


An Overview of CAIRO

The principles of CAIRO unification may be summarised as :

  for radio network voice-message services, particularly at emergencies
Audio Interface        
  the pre-service engineering of communications equipment ;
    A ccessories : devices for listening, speaking and transmission control (PTT)
    B aseband signals : adaptors and line cables for universal electrical compatibility
    C onnections : plugs and sockets (DIN) with a standardised signal-pin format
    D istribution : boxes for multiple terminations and modules for augmentations
Remote Operations        
  the in-service organisation of communications stations
    E fficiency : optimise station layout to meet specific operational requirements
    F lexibility : allow for variable approaches to suit different circumstances
    G enerality : provide sufficient (but not excessive) facilities for most occasions
    H armony : exercise personal preferences in operating styles and techniques


The case for unification through standardisation :

"No man is an Iland, intire of it selfe;
Every man is a peece of the Continent, a part of the Maine ..."

John Donne

The need for unification, through the standardisation of radio equipment (and operating techniques), was first identified within RAYNET - the Radio Amateurs' Emergency Network (UK) and CAIRO was developed as a practical solution for members of that organisation to adopt.

However, CAIRO is equally applicable in other organisations which provide a communications service.

Readers of the material at this Web Site, who are members of other such organisations, are invited to accept that explanations based on RAYNET and its operations, may be taken to include themselves where appropriate.

Equally, they are cautioned that if "Type-Approval" conditions apply to their apparatus, some CAIRO techniques (particularly in CAIRO-8) might contravene that legislation and should NOT be implemented.


During March 2000, I simplified many of the CAIRO site URLs, so I'm sorry if you were first pointed here via a "duff" link.





Supplementary Material

Remote Operations

CAIRO Basics

CAIRO-8 Basics

Raynet Packet

CAIRO Installations

CAIRO-8 Relays

CAIRO Relays

Relay Installations

Summary Configuration

Data Card

Handy Hints



The HOIME = "Here's One I Made Earlier"
CAIRO is an entirely practical idea and to prove it, I am pleased to illustrate several of the chief items with a photograph.
Simply click on such a photo if you wish to enlarge it.
(If the enlargement reveals scratches or dirt on the item, there's your proof !)

Paragraphs with suffix, X, are eXtra (since the paper Manual)

1 Remote Operations
  RO .1 Clerical Organisation
    RO .2 Simultaneous Operations
      RO .3 CAIRO
        RO .4 CAIRO Connectors
          RO .5 CAIRO Configurations
            RO .6 Operator Accessories
              RO .7 Accessory Combinations
                RO .8 Dual Operator Outlet Box
                  RO .9 Auxiliary Features
                    RO .10 Side-Tone Enhancement
                      RO .11 A 'Caution'
2 CAIRO Engineering
  CE .1 CAIRO Signals
    CE .2 CAIRO Connections
      CE .3 Mechanical Integrity
        CE .4 Transceiver Adaptors
          CE .5 Series Adaptors
            CE .6 Active Adaptors
              CE .7 Interface Module
                CE .8 Dual Operator Outlet Box
                  CE .8.X Construction Notes for The Dual Operator Box
                    CE .9 Accessory Engineering
                      CE .10 Binaural Ambience
                        CE .11 Electret Capsules
                          CE .12 Dual Rig Selection Box
                            CE .13 CAIRO Augmentations
  C8 .1 Augmented Operations
    C8 .2 Outlet Socket
      C8 .3 CAIRO-PALS
        C8 .4 Squelch
          C8 .5 d.c.-Power
            C8 .6 d.c.-Regulation
              C8 .7 Audio Line
                C8 .8 Engineering CAIRO-8
                  C8 .9 Surge protection
                    C8 .10 Isolated Audio
                      C8 .11 Opto-Isolation
                        C8 .12 Loose-Tail Connections
4 RAYNET Packet
  RP .1 CAIRO-8 and TNCs
    RP .2 "Clandestine" Packet
      RP .3 DCD Logic
        RP .4 PTT Logic
          RP .5 Acceptability
            RP .6 Relayed "Clandestine"
              RP .7 Portable Packet
                RP .8 Rationale
                  RP .9 DCD-State Boards
5 CAIRO Installations
  CI .1 CAIRO Loose-Tails
    CI .2 Sturdy Lines
      CI .3 Spectral Paints
        CI .4 Portable Sturdy Lines
          CI .5 Anchored Tails
6 Talk-Through : CAIRO-8 Relays
  Variable Network Planning
    TT .1 Temporary Relays
      TT .2 Cross-Band Relays
        TT .3 In-Band Relays
          TT .4 Isolation by Separation
            TT .5 Instant Relays
              TT .6 Wireless Links
                TT .7 Dual-Band Transceivers
                  TT .8 CAIRO-8 TTUs
7 Talk-Through : CAIRO Relays
  CR .1 PALS-Generation
    CR .2 Audio Gating
      CR .3 Noise-Gating
        CR .4 Logic States
          CR .5 Sub-Systems
            CR .6 Anti-Hunting
              CR .7 CAIRO TTU Modules
                CR .8 Bench Set-Up Procedures
                  CR .9 Manning Operator Duties
8 Talk-Through Installations= Relay Installations
  RI .1 Strategic Sites
    RI .2 Grab-Bag
      RI .3 Site-Plan
        RI .4 Frequency Plans
          RI .5 Cross-Band Relay Channels
            RI .6 In-Band Relay Channels
              RI .7 "MEANS" Channels
                RI .8 Talk-Through Permits
                  RI .9 Engineering Channels
                    RI .10 Active Augmenting Modules



Accessories to "Home-Brew"

The Dual Operator Outlet Box

Electret Microphones

The Bus Speaker

The Desk-Top Console

The Palm-Springs The Sturdy Line


Handy Hints Grab-Bag (personal kit) "Black-Bag"
TTRs: Manning Operator Instructions
CAIRO Users If you wish to be included as an "active" CAIRO-ist please E-mail.

Material on this Web Site is based upon a former document (CAIRO Manual): ISBN 1 85449 008 7

©Peter Best - G8CQH

Aston University, Aston Triangle, Birmingham, B4 7ET (UK)

A selection of Web Sites relating to CAIRO, Emergency Communications, Amateur Radio, etc.

G7KPF's Ham Sites Links


GB3EH - a Repeater (RB8) with its Tx and Rx linked to its Logic in CAIRO-8. CAIRO-context Engineering Details

Webmasters : To index into this CAIRO site, please use,

CAIRO - a unified interface for Transceivers

and the URL www.aston.ac.uk/~bestpj/cairo

Logo URL www.aston.ac.uk/~bestpj/cairo/logo.gif