A-STAR Gateway Spec 14 Dec 2010 --------------------------------------------------------------------- WB4APR This note attempts to broadly define the functionality of an A-STAR gateway. An A-Star gateway is identical to a D-star gateway on the D-star side. (at least for the initial understanding). On the APRS side, it does the following: RECEIPT OF A D-STAR QSO REQUEST: When it sees a connect request to its own CALLSIGN, it accepts the connection, brings up the analog repeater PTT and passes D-star audio to the repeater. If there is voice on the repeater input, it passes this back to D-star. The callsign of the A-star gateway is included in the stream. If the analog audio has been identified by an APRS PTT packet, then that callsign is streamed to D-star. If the A-star gateway node sees a connect request to an APRS callsign that it has heard on its own TNC, within the last 10 minutes, it accepts the connection, as above. It also sends out an APRS packet message on the APRS-IS to alert the APRS user that he has a call: FROM: A-STAR gateway APRS-callsign TO: the called callsign MSG: QSY FFF.FFFMHz de [D-Star callee]. RECEIPT OF AN APRS USER-to-D-STAR QSO REQUEST: This request will be heard as an APRS message on the A-Star repeater's input using a simple TNC: FROM: the CALLING APRS user. TO: CALLEE callsign of the called party MSG: A* The A-star gateway will then make this connection via the D-star network using the MYCALL of the APRS Caller, with the URCALL of the CALLED station, with the R1 callsign of the local A-star repeater, and the R2 callsign of the local A-star Gateway. Presumably the A-star repeater will have to use one of the special D-STAR dongles to have the proper A/D and D/A conversions. APRS-DETAILS: Notice, that during any A-star operation, the APRS mobile has his radio's TNC operating on the same band as his voice. The mode will be in PTT mode so that his ID packet goes out whenever he drops his PTT. But at any other time, the APRS user can be tuned to any other frequency as long as his APRS band is on the national APRS signalling channel. THis way, he can receive the incoming QSY message. FOr the D700 and D710 radios different program memories can be used for these modes. PM1 might contain the operators normal APRS and Voice operating mode. But PM2 switches the TNC over to the A-star frequency and places the TNC in PTT mode and puts voice PTT on the same band. The APRS user interface will be as follows: RECEIPT OF CALL (while not on the A-star repeater): He receives an audio message alert and a POP-UP message on the front panel of the radio telling him who has called and what A-star repeater to tune to. In the newer radios, he simply presses the TUNE or QSY button to instantly change his B side (voice) band to the A-Star repeater channel to receive the call. In other words, ONE BUTTON response. RECEIPT OF CALL (while on the A-star channel). Since the APRS operator is already on the A-star channel, the A-star gateway will know that he is alreay there and ready for a call. The APRS operator will simply see a front panel pop-up showing who has called and from where and who is being called. His voice will be heard as soon as he speaks. INITIATE A CALL: He simply tunes his voice band and TNC to the A-star repeater. Then he presses the MSG button, selects a previous A-STAR message, and edits the callee callsign to who he wants to call and presses OK. If the connection is successful he can begin to QSO the called party. The D710 radio keeps the last 100 messages so it is easy to call up a previous connection from preveious calls without having to key-pad it in. Have I missed anything? Bob, WB4APR