Sutron 8310 - GPRS and LAN Session Format

Sutron Corporation 8310 & 7310 Users Manual 8800-1125Rev. 2.7 (BETA) 4/16/2014 pg. 256
GPRS and LAN Session Format
The GPRS and LAN devices send self-timed and alarm transmissions in a special format that
permit the server to also issue commands. This is to allow communication to a device which has
a non-routable IP address. This does not apply to SSP transmissions. The following is a
description of the high-level session format used to encapsulate other formats such as SHEF or
PseudoBinary:
Course of Events
1. Logger connects to Main or Backup Server
2. Logger sends Session Type Code<cr> (see below)
3. Logger sends StationName<cr>
4. Logger sends Report Type Code<cr> to indicate purpose of connection (see below)
5. Logger sends scheduled (or alarm) transmission data (if any)
6. Logger sends ETX (0x03) to mark end of data
7. Logger sends a 3 byte pseudobinary encoded CRC16 of previous data and a shared secret
8. Server sends user login command, !login=username,password<cr> and waits for logger reply
(ETX)
9. If user login matches, logger enters command-line session (see operational details, below)
10. Server issues pending commands, and Logger processes and responds accordingly
11. When command processing complete, the Server disconnects
Session Type Code
"Session type" defines the processing that occurs on connection. Currently, there is only one session type,
"0". This type is defined by the Course of Events above, and details that follow.
"0" = defined by Course of Events, above
Report Type Code
“Report Type code” describes the purpose of the transmission:
"0" = self-timed
"2" = entering alarm
"4" = exiting alarm
"6" = no data, command session only
"8" = forced tx (test tx initiated by user)
Command-line Session Details
The server may precede each command with a "!" to signal machine mode
When processing a command in machine mode, the logger:
Suppresses the command echo
Uses ETX (0x03) as the command prompt (i.e., follows the command response with ETX, rather than the
normal command prompt)
Inhibits pagination (doesn't pause to wait for user input after outputting a full "page" of data)
Alternate Paths
Following send of ETX, logger disconnects the user specific timeout
60 seconds is permitted for login, logger disconnects on failed login