Suntech Protocol · ST300 / ST310U / ST340 / ST600 / ST910 reference
12 devices 11 brands Port 5039 (Traccar / Traxelio reference) TCP (primary) · UDP on battery-saver firmware

Suntech Protocol (ST300 / ST310 / ST340 / ST600 family)

ASCII TCP/UDP protocol designed by Suntech (Brazil) for the ST300, ST310U, ST340, ST380, ST600, and ST910 fleet/lone-worker tracker families. Dominant across LATAM rental, fleet, and cargo-tracking deployments.

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3 min read · ~426 words

Quick answers

Is Suntech the same as Sun Telecom?

No. Suntech Innovations is the GPS tracker manufacturer in São Paulo, Brazil. Sun Telecom is a different optical-equipment company in China. Confusion is common because Suntech's catalog is also sometimes labeled "ST series" · which is the same prefix used in the model names (ST300, ST340, ST600).

What does the leading token mean in a Suntech packet?

It's <model><record_type>. ST300STT = ST300 status report (positions). ST300EVT = event-triggered report (ignition, panic, geofence). ST300ALT = alert (overspeed, hard brake). ST300CMD = command response. The model prefix lets one parser handle multiple device generations.

Does Suntech use TCP or UDP?

TCP by default; UDP on some lone-worker / battery-saver firmware where keeping a TCP session open would drain the battery. Both transports speak the same ASCII grammar · the parser doesn't care.

Can Suntech devices push server commands?

Yes. Send an ST300CMD;<serial>;<cmd_code>;<args>;\r to the device's TCP socket and it acks with a matching ST300CMD; response. Commands cover relay engage/disengage, parameter changes, firmware update, immediate location request. The lone-worker ST910 also accepts SMS commands for emergency-recovery scenarios.

Does Suntech support CAN-bus or J1939?

On the ST380 and ST600 fleet variants, yes · with an optional FMS / J1939 reader cable. The base ST300 / ST340 / ST310U do not have CAN input. For heavy-truck telematics with full CAN depth, the ST600 is the go-to in the Suntech lineup; outside it, look at Teltonika or Ruptela.

The Suntech protocol is the ASCII wire format spoken by every device shipped by Suntech Innovations (Sao Paulo, Brazil) since the early ST200 series. If you operate a fleet in Brazil, Argentina, Mexico, or Colombia, you have almost certainly seen ST300STT; packets land on your server · Suntech is the most-deployed fleet-grade tracker brand in LATAM, and the protocol has stayed remarkably stable across more than 15 years of hardware revisions.

Protocol-at-a-glance

  • Transport · TCP (primary) or UDP (some firmware revisions)
  • Default port · 5039 (Traccar reference; Traxelio matches this)
  • Encoding · ASCII, semicolon-delimited fields, terminated by (CR)
  • Auth · No separate login packet · device IMEI / serial is in every message header
  • Heartbeat · Keep-alive messages (ST300KAL; or model variant) sent on a configurable interval
  • Spec · Suntech publishes the protocol PDF for integrators on request via their partner portal

Packet structure (essentials)

Every Suntech packet follows the same shape:

ST300STT;205000000;04;FW;DATE;TIME;CELL;LAT;LON;SPEED;COURSE;SATS;FIX;DISTANCE;POWER;IO;MODE;MSG_NUM;
  • The leading token is the model + record type (ST300STT = ST300 status, ST300EVT = event, ST300ALT = alert, ST300CMD = command response)
  • Fields are positional, semicolon-separated · the parser keys off the leading token, not field names
  • ASCII format makes it cheap to log, grep, and replay · which is part of why Brazilian fleet integrators love it

Why Suntech is the LATAM fleet default

  • Local presence · São Paulo R&D + manufacturing, local support, Portuguese-language integrator docs
  • Range coverage · ST300 (basic), ST310U (USB-config OBD), ST340 (rental/light fleet with relay), ST380 (heavy fleet + CAN), ST600 (premium fleet), ST910 (lone-worker)
  • ANATEL homologation · most models ship pre-certified for Brazil, a real cost-saver vs importing Asian OEM hardware
  • Protocol stability · the same parser written in 2012 still decodes 2026-firmware packets · long upgrade paths

Configuring a Suntech device for any server

Two paths · SMS commands or the SunSuite configurator:

SMS path (works on ST300, ST310U, ST340 with a SIM):

ST300CMD;205000000;02;Network;your-server.com;5039;
ST300CMD;205000000;02;APN;internet;username;password;
ST300CMD;205000000;02;Report;30;60;0;

(Replace 205000000 with the actual device serial, your-server.com:5039 with your server.)

SunSuite path: connect via USB, point at the server IP+port, click Apply, power-cycle. SunSuite is Windows-only but works under Wine.

After a clean boot with GPS lock, confirm the first decoded position in Traxelio.

Supported devices in our catalog

Suntech ST300 / ST310U / ST340 / ST380 / ST600 series are catalogued under protocol: "suntech". The headline models are ST300H (low-cost truck), ST310U (OBD-II plug-and-play), ST340 (relay-equipped fleet), and ST910 (panic-button lone-worker).

Setup walkthrough

  1. 1

    Insert SIM with data plan + airtime

    Verify the SIM has an active LTE/3G data session in a phone first. Suntech devices have no UI to surface SIM / APN failures · a dead SIM looks identical to a working one to the device's status LEDs.

  2. 2

    Connect over USB or SMS for first config

    ST310U and newer revisions accept USB config via SunSuite (Windows / Wine). Older ST300 / ST340 are SMS-only. Either path works · the SMS commands ride on the same parameter store.

  3. 3

    Point the device at your server

    Send the Network command with your server's hostname and port. Replace your-server.com:5039 with whatever endpoint your platform exposes for the Suntech ASCII protocol.

    ST300CMD;<device_serial>;02;Network;your-server.com;5039;
ST300CMD;<device_serial>;02;APN;internet;;
  4. 4

    Set reporting cadence

    ST300CMD;<serial>;02;Report;30;60;0; reports every 30 s moving, 60 s stationary, 0 = position-only. Tighten for fleet ops (10 s / 30 s); loosen for battery-saver lone-worker (300 s / 600 s).

  5. 5

    Confirm first position arrives

    Send ST300CMD;<serial>;01;Status; and watch your server log. After a clean boot with GPS lock, confirm the first decoded position in Traxelio. No response after the reboot · re-check APN (most common silent failure).

  6. 6

    Don't have a Suntech-compatible server yet?

    Traxelio decodes Suntech ASCII natively on port 5039. Send ST300CMD;<serial>;02;Network;traxelio.com;5039; and the first decoded position can be verified in Traxelio · including relay-command support on ST340/ST600. Or self-host Traccar · same decoder, same port.

Reference

Configuration reference

Parameter Value
Transport TCP (primary) · UDP on battery-saver firmware
Default port 5039 (Traccar / Traxelio reference)
Encoding ASCII, semicolon-delimited, CR (`\r`) terminator
Packet header Model + record type prefix (e.g. `ST300STT;`)
Packet footer Carriage-return (0x0D)
Authentication Embedded · device serial in every message header (no separate login)
Heartbeat Keep-alive `ST300KAL;` (or model variant) at configurable interval
Checksum None at protocol level · TCP transport handles integrity
Message types STT (status), EVT (event), ALT (alert), CMD (command), KAL (keep-alive), RES (reservation)
Configurator SunSuite (Windows · Wine-compatible)
Spec portal Suntech integrator partner portal (PDF on request)
Open-source decoder Traccar `SuntechProtocolDecoder` is the most authoritative open reference
Vendor Suntech Innovations · São Paulo, Brazil

SMS commands

ST300CMD;205000000;02;Network;your-server.com;5039;

Point the device at a server (replace serial + host + port).

ST300CMD;205000000;02;APN;internet;;

Set the SIM's APN (third + fourth fields are optional username/password).

ST300CMD;205000000;02;Report;30;60;0;

Report every 30 s when moving, 60 s when stationary.

ST300CMD;205000000;04;Output;1;1;

Engage the relay output (on supported hardware). `0;` releases.

ST300CMD;205000000;03;Reboot;

Soft-reboot the device to apply parameter changes.

ST300CMD;205000000;01;Status;

Query device status · returns GPS / GSM / server-connected diagnostics.

Or skip the integration

Traxelio decodes Suntech natively

Point your device at our endpoint, then verify the first decoded position in Traxelio. We handle the protocol, ack the packets, and serve the dashboards.

Plan a protocol cutover Talk to integrators

Protocol Capabilities

Data Points from Suntech Devices

Traxelio processes all telemetry data sent by Suntech trackers for comprehensive fleet insights.

Core Tracking

  • GPS Location
  • Speed
  • Altitude
  • Heading / Direction
  • Street Address
  • GPS Accuracy

Engine & Driving

  • Ignition Status
  • Odometer / Mileage
  • Engine Hours

Sensors

  • Battery Level

Event Coverage

Alerts you'll get from devices on this protocol

Device online

The device is back online and transmitting data.

Device offline

The device has stopped reporting. It may have lost connection or power.

Device Moving

The vehicle is currently in motion.

Device Stopped

The vehicle is stationary.

Device overspeed

The vehicle is exceeding the set speed limit.

Geofence enter

The vehicle has entered a defined zone.

Geofence exit

The vehicle has exited a defined zone.

Alarm

Tow

Possible towing activity detected, check vehicle status.

Ignition On

The ignition is ON. The engine has started.

Ignition Off

The ignition is OFF. The engine has been stopped.

Long Idle

The vehicle has been idling for a long period.

Hard Braking

Hard braking detected, driver safety alert.

Hard Acceleration

Rapid acceleration detected, driving behavior alert.

Hard Turning

Sharp turning detected, driving behavior alert.

Impact Detected

Potential impact detected based on sudden deceleration and course change pattern.

All Models

Representative Suntech Devices (12)

Start with the strongest matches, then use pagination or brand pages for the full compatibility list.

ST200

ST200

ST210

ST210

ST215

ST215

ST215E

ST215E

ST215I

ST215I

ST230

ST230

ST240

ST240

ST410

ST410

ST900

ST900

ST910

ST910

ST-910

Suntech

ST-940

Suntech

Compatible Brands

Brands Using Suntech Protocol

Suntech

2 devices

ST200

1 devices

ST210

1 devices

ST215

1 devices

ST215E

1 devices

ST215I

1 devices

ST230

1 devices

ST240

1 devices

ST410

1 devices

ST900

1 devices

ST910

1 devices

Common troubleshooting

Device sends position once, then stops · server keeps the TCP socket open but no further data arrives

Almost always a NAT / firewall keepalive issue on the carrier side. Suntech keeps the TCP socket open between reports; some LATAM carriers tear the NAT entry after 5-10 min of silence. Fix: enable the device's keep-alive (ST300CMD;<serial>;02;Keepalive;180; for a 3-min ping) or accept reconnects on every report by setting Report interval below the carrier's NAT timeout.

ST310U powers off when the engine is off · positions lost

ST310U draws power from the OBD port, which most vehicles cut when ignition is off. The internal backup battery is small (typically 30-60 min). Either accept the gap (most fleet use cases don't care about parked-vehicle positions) or wire the device to switched-and-constant power via the OBD harness · Suntech sells the cable.

Panic-button alerts from ST910 don't arrive · status reports work fine

Panic events ride on a separate ST910EMG; (emergency) packet shape with higher priority. If your decoder only handles STT and EVT, panic alerts silently drop. Add EMG, ALR, and ALT to your message-type whitelist · all standard Suntech messages, but each has its own decoder branch.

Explore More

Other Protocols

GT06

99 devices

H02

91 devices

Teltonika

84 devices

Meiligao

59 devices

GL200

36 devices

GPS103

31 devices
View All Trackers

FAQ

Frequently Asked Questions

Is the Suntech protocol open / publicly documented?

It is documented but distributed under integrator NDA · Suntech sends the PDF on request via their partner portal. The open-source Traccar project ships a complete SuntechProtocolDecoder covering all known message types, which is the most accessible reference for a working implementation.

Does Suntech work outside LATAM?

Yes · the protocol is region-agnostic. The hardware is most common in Brazil, Argentina, Mexico, Colombia, Chile, and the rest of Spanish-speaking LATAM because of Suntech's local presence and certifications, but the same devices work in Africa, Asia, and Europe with the right APN. ANATEL homologation is a Brazil-specific feature; outside Brazil, any GSM modem certification covers the same hardware.

What's the difference between ST300H and ST310U?

ST300H is the basic hardwired tracker (3-wire installation, internal antenna, no inputs/outputs to speak of · the budget option for vehicle tracking). ST310U is the OBD-II plug-and-play version (1-min installation, no wiring, USB-config) · same protocol, very different installation cost and target use case.

Can I run Suntech and GT06 devices on the same server port?

No · they speak different grammars (ASCII semicolon-delimited vs binary 0x78 0x78 headers). One decoder cannot handle both. Run them on different TCP ports (e.g. 5039 for Suntech, 5023 for GT06) and let the listener bind separately. Traxelio and Traccar both follow this port-per-protocol pattern.

How does Suntech handle offline buffering?

Most Suntech firmware buffers a configurable number of position records in flash when the GPRS link is down (typically 5000-10000 records). On reconnect, buffered records are sent with their original timestamps · server-side, your code needs to handle out-of-order arrival and not over-write a newer position with an older buffered one.

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