Bob Bruninga has updated his recommended SSID suggestions. The big change is that before it was keyed mainly to choose the symbol and now it is purpose driven. For example, it's not that -9 is a car, now it's the main mobile.
The complete publication is at : http://aprs.org/aprs11/SSIDs.txt
Here's the main content.
APRS SSID Standard Applications 9 June 2010
Updated 9 June 2010 for more flexibility
Revised 2 June 2004 to add -10, -11, 12 and -15
SSID's have seen two different uses in APRS. Initially as an ICON indicator back in the early 1990's. But that is obsolete for over a decade. Now SSID's are used as an informal way of indicating one of several different typical APRS applications.
Since many small displays for the handheld and mobile operator show nearby APRS station callsigns that flash up on the screen, it is nice to have some idea of what type of station or activity might be involved simply from the callsign SSID without having to push buttons, search lists, or look at maps to find out more about them.
SSID RECOMMENDATIONS: It is very convenient to other mobile operators or others looking at callsigns flashing by, to be able to recognize some common applications at a glance. Here are the recommendations for the 16 possible SSID's (the limit of 16 comes from the 4 bits available in the AX.25 protocol. Note, The SSID of zero is dropped by most display applications. So a callsign with no SSID has an SSID of 0.
- -0 Your primary station usually fixed and message capable
- -1 generic additional station, digi, mobile, wx, etc
- -2 generic additional station, digi, mobile, wx, etc
- -3 generic additional station, digi, mobile, wx, etc
- -4 generic additional station, digi, mobile, wx, etc
- -5 Other network sources (Dstar, Iphones, Blackberry's etc)
- -6 Special activity, Satellite ops, camping or 6 meters, etc
- -7 walkie talkies, HT's or other human portable
- -8 boats, sailboats, RV's or second main mobile
- -9 Primary Mobile (usually message capable)
- -10 internet, Igates, echolink, winlink, AVRS, APRN, etc
- -11 balloons, aircraft, spacecraft, etc
- -12 APRStt, DTMF, RFID, devices, one-way trackers*, etc
- -13 Weather stations
- -14 Truckers or generally full time drivers
- -15 generic additional station, digi, mobile, wx, etc* One-way trackers can use any symbol the owner desires, -9, etc but if the owner wants to indicate that a particular mobile is not message capable and he cannot receive message traffic, then he might want to use the -12 indication.