Spec for Voice-Internet NODE Status on APRS [AVRS] Rev 3 --------------------------------------------------------------------- 23 Jun 2003 WB4APR Automatic Voice Reporting System AVRS AVRS is a generic term that applies to any Voice-over-IP system that uses APRS to augment the end-user data delivery and display of system status and/or end-to-end signaling between users of these systems. Thus AVRS refers to all of the systems: One early objective of AVRS is for IRLP, I-LINK, ECHO-Link and any other Voice-to-Internet interfaces to HAM radio to transmit a status packet to local APRS users whenever the node changes state. These status packets show up on the front panel of APRS radios or other display devices to alert APRS mobiles of the current state of all nodes in RF range. The normal APRS front-panel display can show the following information about a node: NAME Node geographic name or Node Number State: Off line, idle, in use, Connected, Conferenced. Position: Coordinates of Node Distance: Distance from mobile (computed by mobile) Bearing: Direction from mobile (computed by mobile) (an arrow) Freq: Frequency of node PL: PL of node if used or if public Link: Callsign or name of station connected Type: Type of Node, IRLP, I-Link, ECHOlink, etc All of this is transmitted in a single APRS OBJECT (ITEM) packet by a TNC connected to the PC comm port. The node software simply has to send an ASCII string to the serial port whenever the node changes status. A TNC connected to the serial port and a radio on 144.39 (USA) completes the hardware requirements. NOTE: Eventually we hope all NODES will convert to an alphabetic NAME instead of a NODE number. This is far more user friendly. For example, of the node in Annapolis Maryland the name would be MDannapls and when typed on a Touch-Tone DTMF pad, the equivalent node number would be MDAnnapls ==> 63266757 This way no one has to remember node numbers, just NODE names. I call this process "hashing" the name in to a DTMF string. All nodes begin with their two digit STATE or COUNTRY abbreviation. But this will take evolution of the existing system to include the additional digits necessary. But in the mean time, NODE operators can CHOOSE numbers that at least approximate their Touch-Tone hash code of their geographic name. For example, the node at NASA in Greenbelt Maryland could choose 6272. Or Annapolis could choose an echolink number of 26627. INTERIM PLAN: ------------- But until we get the IRLP or ECHOlink node systems to switch to alphabetic node names, we will use the node TYPE and NUMBER for now. Such as IRLP-7070 or ECHO12345 SAMPLE DISPLAYS ON THE TH-D7 HT for ECHOLINK NODE NAMED MDAnnapls: +-------------+ This is the station list. It contains the last | 1:MDAnnapls | 40 entries heard. It shows 2 nodes on line and | 2:DCWash-03 | one, MD-NASA as being connected. You can tell | 3:MD-NASA | it is connected because it is all UPPERCASE. +-------------+ (But this is future objective) +-------------+ This is how things will actually appear until we can | 1:IRLP-7070 | convince everyone to switch to node names. Notice | 2:ECHO12345 | The node fits in the list just like any other APRS calls | 3:WB4APR-9 | heard. +-------------+ +-------------+ Each time a new status comes in, it is displayed for | 1:IRLP-7070 | 10 seconds as shown here. It shows that it is | 146895-107 | on 146.895 MHz with - Offset and PL of 107. | OFF @1345 | It is also the first display page for Station #1 +-------------+ +-------------+ | 1:IRLP-7070 | This is page 3 showing the node is in FM19SX | FM19SX | and is 13.5mi east |/L 13.5mi => | +-------------+ +-------------+ | 1:IRLP-7070 | This is page 5 showing the node is running | pw49W h0400'| about 50 watts to a 6 dB omni antenna at 400' | ant6dB omni | Normal APRS programs will display a range circle +-------------+ computed from this information. +-------------+ | 1:IRLP-7070 | The state just changed to "connected to the | 146895-107 | node number 8315" | => 8315 | +-------------+ The Kenwood D700 mobile displays similar information, but because of its larger screen, it displays it all on one page. PACKET FORMAT: -------------- The format of the string is in APRS "OBJECT" format as follows: ;nnnnnnnnn*DDHHMMzDDMM.HHN/DDDMM.HHWLPHGphgdFFFFFF+PPPyyyyyyyyyyzzzzzzzz Where: nnnnnnnnn is the 9 character node Name or Callsign DDMM.HHN DDDMM.HHW is the LAT/LONG of the node L is a the Link ICON character "PHG" are required characters indicating the next 4 chars are: p is power h is HAAT g is antenna gain d is directivity FFFFFF+ppp frequency in KHz, offset, and PL in whole number Hz yyyyyyyyyy 10 Status bytes (Second line on a TH-D7) zzzzzzzz 8 optional bytes shown on the D700, but not the D7 Formats for the NNnnnnnnn Name or Callsign Field: (When we get around to it) REPEATER: Then NN is the state and nnnnnnn is the city INDIVIDUAL: NNn is the type IR-, IL-, EC- and nnnnnn is call STATUS: This is the key. The CASE of this field indicates four operating states: uullllllll - shows offline UUllllllll - Shows on line or idle UULlllllll - Shows Connected UULLLLLLLL - Shows conferenced. Formats for NODES using existing numbering schemes depend on the number of digits. Four and Five digit systems fit well. As we go to larger number of digits, then the leading TYPE characters can be shortened to IP, EO, or IL, etc: IRLP-#### for four digit IRLP nodes ECHO##### for five digit Echolink nodes I-LK-#### for I-Links Formats for FFFFFF/ppp: Notice that this is a 10 byte field driven by the fact tht both the D7 and D700 display such text in a 10/10 format for the D7 and a 10/10/8 format for the D700. The following variations on this format are permitted: FFFFFF+ppp Can show a + or - repeater offset. FFF.FFF- Decimal point fits if there is no PL FFFFFF/ppp Is simplex or no offset is given Formats for the variable field YYYYYYYYYY and ZZZZZZZZ: Again, the YYYYYYYYYY field is 10 characters and is displayed on both the D7 and D700, but ZZZZZZZZ is only displayed on the D700. Therefore the following formats are suggested. Notice the leading space or punctuation mark to make this more readable on devices other than the Kenwoods where these fields are concatonated together in the actual packet: Node State YYYYYYYYYYZZZZZZZZ Comments ---------- ------------------ ----------------------------- Offline: " Off @HHMM........" can contain some comments in Z On-Line: " On @HHMM........" Time it returned to ON (+Z if any) Busy: " Busy HHMM.3 nodes" Time it went busy & # of nodes Connected: "=NNnnnnnnn at HHMM" Shows call/Name of connection "+NNnnnnnnn at HHMM" if another one connects TIMING: The status packet should go out whenever the node changes state, or once every 10 minutes. PATH: These packets should go DIRECT if the Node is physically at the RF site, because the packet will have the same RF coverage area. If it is necessary to hit a digipeater, then ONLY hit ONE HOP (via WIDE). There will be a lot of these packets and we dont want to kill the golden goose by overloading the APRS system. Keeping them DIRECT keeps any QRM issues totally local.. APRS TNC PARAMETERS: The TNC connected to the COMM port needs to be in converse mode so that the ASCII string is transmitted when it is sent to the COMM port. These TNC settings are recommended: MYCALL is your callsign. It is not meaningful in AVRS UNPROTO APVInn VIA WIDE For IRLP, with nn as software version or APVEnn VIA WIDE For ECHOlink BEACON EVERY 0 Turn off all beacons unless you have a specific reason for on. JUSTIFICATION: IRLP, I-LINK and ECHOlink will revolutionize voice HAM radio just like APRS and Steve Dimse's APRS-IS have revolutionized packet radio. APRS in this case is the end user data system for delivering tactical real-time data to the mobile user which is of immediate value to him. Kenwood has also made all this possible by giving us a target end user display system to which we can push this formatted information. Now, this is only the beginning. Here are the NEXT steps in the evoluion: NODE NAMING: ------------ The objective of AVRS is to be system transparent to everything except the end user's callsign. If I want to talk to WB4APR by voice anywhere on the planet, then all I should have to do is enter the callsign. APRS should know where he is, IRLP/ECHO link can make the connection, so we already have all the tools. But, so that ANYONE can use the advantage of AVRS, not just APRS mobiles, the obvoius comon denominator is the ubiquitous DTMF pad. This is why the TOuchTone system was developed for APRS as APRStt. But to facilitate callsign entry, APRStt uses "Touch-Tone callsign hashing". That is you simply spell out the callsign on the Keypad. Thus, every callsign has a unique 4 to 6 digit number hash. Only about one call in every 1000 will have similar hash codes. In those cases, the node simply reads back all those that matched and are on line, and ask the sender to select the right one. For WB4APR, the HASHED call is 924277 This should be my ECHOlink node number. REPEATER NAMES: Now, with 60,000 repeaters involved, the callsign of a repeater means practically nothing outside of its supporting club. Thus, REPEATERS or LINKS that support multi-users should use NAMES that either refer to the geographic location, or to the name of the club. Since APRS supports a 9 character packet call, then these names must be limited to 9 characters as follows: NNnnnnnnn Where NN is the STATE abbreviation in the USA/Canada Where NN is any other distinct 2 letter country code nnnnnnn Is the City or other distinguishing letter group. For example, DCwash03 Might be the 3rd IRLP repeater in Washington DC, MDnasa might be the repeater at the NASA Goddard center in Greenbelt Maryland. VAamrad might be the AMRAD repeater in Virginia. Again, these NAMES automatically convert to a TouchTone HASH code. In this case MDnasa is 636272 Or MD-NASA is 6306272 Phasing in these new node numbers is easy. In APRStt, all HASH coded callsigns are preceeded with a "0" to indicate it is a hashed call. If it doesnt start with a "0" then it is an existing NODE number or it is a fully spelled out callsign. In this case, WB4APR on the TTone pad is 922444427A77 when fully spelled out. The "A" key is a separator when two adjacent letters are on the same TTone key. The TTOne HASH plan is: QZ1 ABC2 DEF3 GHI4 JKL5 MNO6 PRS7 TUV8 WXY9 * _0 # MULTIPLE NODES PER CALL: Just like Packet allows up to 16 differnet SSID's under a single callsign, the inventiveness of HAM radio operators will require multiple uses per call. Following on the ECHOlink definition of -R and -L for Repeaters and links, this convention can be extended to a total of 9 different stations subtypes. Here we carefully make sure there isa one-to-one correspondence to TTone keys so that we have no ambiguity. Here are my suggestions for the 9 station types: KEY LTR MEANING ---- --- ------- 1QZ Q Qth 2ABC C Club station 3DEF E EOC or other emergency station 4GHI H HF station 5JKL L Link station 6MNO M Mobile station 7PRS R Repeater 8TUV T Telephone link (local calls) 9WXY W Work station Thats all there is to it. The result will be a revolution in HAM radio, because now users can see on the tiny-web-pages of their radio, the status of all nodes (known or unknown) that are in range, no matter where they are. And the Frquency, PL and status are also shown. Later we can add all the additional leveraging ideas that I have been talking about for using APRS as an adjunct to VOICE Internet interfaces to HAM radio.. de WB4APR, Bob