The Evolution of Codan Selcall In the beginning

The Evolution of Codan Selcall. . . In the beginning God created 493. 1 (Kyoto 1978) by means of CCIR 1

Basic 4 Digit Selcall. . . And 493. 1 begat the Codan selective calling system - Selcall which gathered many users to the clan Codan because it gave them: • Robust individual addressing for calling on an HF network. • The possibility of using scanning intelligently by allowing the calling transceiver to stop the called transceiver on an appropriate frequency • The possibility of a mute which only opened when that particular transceiver was called (the first really effective HF mute system). . . and Codan was glad to have many users in the southern kingdom 2

The coming of the Giant Users. . . and there were giants in the land at that time and they came to Codan and said “We want to become Giant Users”. The first Giant User was Giant Hi Commotion who spread Codan selcall to all corners of his empire. But Giant International became very red and cross and did not want to become a Giant user at this time and neither did Giant Federation. Now Giant Oxford, Giant Food Provider and Giant Childrens’ friend became part time users because they were not sure of the son of 493 -1 3

Beacon calling 99 & selective. . and Codan said unto himself ”let us make it possible for User and Giant user to test frequencies before calling his base station” and so he created 99 beacon which gave User: • The possibility for mobiles to determine the best frequency before calling the central station. . . and Codan said to himself “it is not good that only one station should be able to respond to a beacon call” and so he created Selective Beacon so that : • Any station could find the best frequency for contact with any other station by selective beacon calling 4

Telephone Calling. . and users from the antipodes came before Codan and said “Your users are not happy just talking to other radio users we want to talk to telephone users”. And so Codan took Selcall and added Telcall to it because his users cried out to him. Thus : • Automatic radio to telephone and telephone to radio calls could be made using both preset numbers and free dialing. . . and the users were content. 5

Emergency calling. . . Then there wars and famine and pestilence in the lands and Giant Hi Commotion summoned Codan before him and said “We are a harried and pressed people and do not have time for selcall numbers and frequency choice when disaster strikes and our fingers tremble” And Codan was greatly troubled by this and summoned his radio blacksmiths to advise him in his southern kingdom. After consulting all the omens Codan added Emergency call to selcall at the behest of Giant Hi Commotion 6

Emergency calling 2. . and so it was that user and giant user could have: • A single Emergency call button which when pressed for 3 seconds automatically switched to an emergency channel and sent an emergency selcall to the master station. • This resulted in alarm signals over the frequency and in the master station to summon help and a display on the radio to show who was in trouble and on which channel they could be called. At this time Codan also started the rites of selcall lockout and auto antenna tune for the good of the many. 7

The Great Gathering of Giant Users . . . Now about this time there was a softening of many hearts amongst the Giants International and Federation although still red and cross, believed Codan’s message of user service and became Giant Users. Further Giant food provider, Giant Child Friend, Giant Oxford and many other Giants joined the Codan clan. Giants came even from the world of Nonaid like Giant Beepex to swell the Codan clan. 8

Pagecall & GPS calling. . . and Codan said to himself “truly such ingathering of the tribes and loyalty deserves new revelation”. So he set himself and the radio blacksmiths a mighty task to allow users to send written messages using selcall and to tell other users where they were without speaking. Thus it was as the millennium drew to a close that Codan users could : • Send & receive 64 character paging messages with confirmation of arrival error free. • Send and receive GPS position reports. . . and user and giant user alike rose up and pronounced it a marvelous thing that Codan had done 9

Status call But Codan could not rest from his labours for some users had come to him in dead of night and whispered “how shall we know if another users radio is working well” and so spurred on by this challenge Codan took Selcall one last time and fashioned it into status call that the user might know how fared his friend’s radio in the storms of life without having to ask him, by providing : • Diagnostic call to know the state of the radio. • Configuration call to know how the radio is set up. • and User call to command things to happen at another site. 10

And they all lived happily ever after . . . And user and giant user said unto Codan “truly you have provided us with a wealth of features beyond our dreams and imagination. How can we thank you” Codan said to them “Go forth and communicate throughout the world, multiply users wherever you find need and I will be content” 11

Selcall Summary • Selcall – – – Purpose - initiate voice contact 4 digit & 6 digit No privacy coding RX alert - 3 x dual phone rings TX revertive - 5 beeps • Group call – – – 12 Purpose - alert for broadcast 4 digit & 6 digit No privacy coding RX alert 15 beeps TX revertive none

Selcall Summary • 99 Beacon call & selective beacon call – – – Purpose - Test link quality 4 digit & 6 digit No privacy coding RX alert - none TX revertive 4 long tones • Telcall – – – 13 Purpose - Initiate telephone link 4 digit, 6 digit & 6 digit + ESN (RDD) 4 digit open, 6 digit coded RX alert - none TX revertive di dah

Selcall Summary • Pagecall – – Purpose - sending text messages 4 & 6 digit plus the text string Can be protected with privacy key RX alert - 3 groups of 5 beeps + “Message from XXXX” on display – TX revertive - bip-bip + “Pagecall succeeded” on display • Emergency call – – – 14 Purpose - to declare an emergency 4 & 6 digit plus optional GPS position Can be protected with privacy key RX alert - Hee-haw tones for 5 minutes TX revertive - Rising whoop siren

Selcall Summary • Status call - Diagnostics – Purpose - Obtain diagnostic test information from a remote station – 4 & 6 digit plus the information string – Can be protected with privacy key – RX alert - None – TX revertive - Information string, no tones • Status call - Configuration – Purpose - Obtain configuration information from a remote station – 4 & 6 digit plus the information string – Can be protected with privacy key – RX alert - None – TX revertive - Information string, no tones 15

Selcall Summary • Status call - User – Purpose - Send a command to a computer at a remote station – 4 & 6 digit plus the information string – Can be protected with privacy key – RX alert - None – TX revertive - reply string from the remote computer, no tones • Send GPS info – – – 16 Purpose - send GPS position to a remote station 4 & 6 digit plus the GPS position Can be protected with privacy key RX alert - 3 x 5 beeps + GPS position TX revertive - 4 long tones

Selcall Summary • GPS Beacon call – – – 17 Purpose - collect GPS position from a remote station 4 & 6 digit plus the GPS position request Can be protected with privacy key RX alert - none TX revertive - GPS position on display