Conversations

Conversations are a mechanism used by the gateway to track messages between SMS users and APRS users. They temporarily associate the APRS user’s callsign with the SMS user’s telephone number.

Sending a message from an APRS station to an SMS number (or vice versa) initiates a conversation. For the duration of the conversation, it is not necessary for either party to include the destination in their message allowing for quicker, more natural replies. This saves time and reduces the number of characters that must be entered with each message.

Endpoints (both APRS stations And SMS handsets) can participate in multiple conversations. Responses will automatically be sent to the most recent active conversation. To switch conversations, one need only specify the callsign or number of the destination. When multiple conversations are live, however, it is important to remember that the last message sent or received will change the active conversation.

Example (from the APRS perspective, using aliases for clarity):

-> @jack Jack, just made it to the summit.
<- @dave Dave, How far behind are you?
-> @dave 10 minutes tops
-> Ok, see you soon (delivers @dave)
<- @jack Took you long enough ;)
-> I think I beat your time. (delivers to @jack)
<- @jack maybe
-> @dave I can see you now.
<- Excellent (delivers to @dave)
-> @jack dave has just made it.

Since all the messages are being sent to the same destination callsign (SMSGTE), they will all appear in the same message stream, which can be confusing. An SMS user would have a similar experience if they were conversing with two or more APRS at the same time because the destination phone number is the same for all APRS users in a region.

Using SSID aliases does make this a little less complicated, as the client or radio will treat each callsign/SSID combination as a unique destination creating separate message streams for each one. Using SSIDs, the conversations above would look more like this:

-> Jack, just made it to the summit.
<- Took you long enough ;)
-> I think I beat your time.
<- maybe
-> dave has just made it.

<- Dave, How far behind are you?
-> 10 minutes tops
-> Ok, see you soon
-> I can see you now.
<- Excellent

Killing a Conversation

An APRS station can choose to end a conversation with an SMS endpoint without waiting for the inactivity timer to expiry. This may be useful if the SMS user is sending abusive or otherwise unwanted messages. To kill a conversation, simply send the kill command with the number or alias of the SMS user. This command is only valid from APRS. Numbers on your alias list will still be able to initiate new conversations using your callsign. The command uses the following syntax:

 #kill {all, <number>} 

#kill represents the command being used. You can either choose to kill a specific conversation by specifying the destination number or alias, or you can choose to kill all active conversations.

Example:

To: SMSGTE
#kill 6135551234

To: SMSGTE
#kill all