GPS103 Protocol · Coban TK103 ASCII format, SMS commands
31 devices 2 brands Port 5001 (Traxelio) · 9001 (Coban ref) · 5002 (TK103 variant) TCP

GPS103 Protocol (Coban TK103 family)

ASCII TCP protocol designed by Coban Electronics for the GPS103 / TK103 / TK303 family · the oldest and simplest budget-tier wire format still in production. Used by Coban and dozens of OEM rebrands.

Talk to integration team Browse 31 supported devices Read the spec

3 min read · ~455 words

Quick answers

Is GPS103 the same as TK103?

Same family, different revisions. GPS103 is Coban's original packet shape (port 9001/5001 typically). TK103 is the later revision (port 5002 typically). Both are ASCII, both come from Coban. Most operators treat them as one umbrella but Traxelio (and Traccar) decode each correctly via separate port-mapped decoders.

What does a GPS103 position packet look like?

Plain ASCII text, semicolon-delimited: imei:359710040128345,tracker,250531180000,,F,180000.00,A,1442.7250,N,01708.7060,W,0.00,;. Fields are IMEI, command, timestamp, phone, validity, UTC time, fix-quality, lat, N/S, lon, E/W, speed. Human-readable in a raw TCP dump.

What port does GPS103 use?

Configurable. Traxelio uses 5001 (TCP, matches Traccar's default). Coban's reference docs commonly say 9001. The SMS adminip command sets whichever port the server expects.

How do I send commands to a GPS103 device?

Two paths · SMS commands (sent to the device's SIM phone number) or server commands over the same TCP channel (some Coban firmware accepts inbound commands; many older units only accept SMS). For reliability, use SMS for one-off operations and TCP commands for recurring tasks like position-frequency changes.

Does GPS103 support engine cut / immobilizer commands?

Yes on devices with the relay wired (Coban 303F, GPS103 with relay variant). SMS command: stop123456 to engage, resume123456 to release. The relay physical wiring varies by install · the device needs the right output pin connected to the ignition / fuel pump line.

The GPS103 protocol (also known as TK103 protocol) is the original Coban Electronics wire format for the GPS103 / TK103 / TK303 / Coban 303 hardware family. It is ASCII text-based, comma-separated, deliberately simple · designed when 2G modules cost $15 and every byte counted. Almost two decades later it is still in production because the Coban GPS103 hardware reference design remains the cheapest credible GPS tracker on the market (~$10 in volume).

Protocol-at-a-glance

  • Transport · TCP
  • Default port · 5001 (Traxelio's ingest port; Coban's reference is 9001 or operator-assigned)
  • Encoding · ASCII text, semicolon-delimited fields, fixed packet shapes per command
  • Auth · Login packet carries IMEI; server returns LOAD to acknowledge
  • Heartbeat · Device sends keep-alive every ~3 minutes (configurable)

Packet examples

A login looks like:

##,imei:359710040128345,A;

A position record (Coban GPS103 standard format):

imei:359710040128345,tracker,250531180000,,F,180000.00,A,1442.7250,N,01708.7060,W,0.00,;

Fields (in order): IMEI · command type · timestamp · phone · validity · UTC time · GPS-fix-quality · latitude · N/S · longitude · E/W · speed.

The simplicity is the point · any language with a string-split function can decode it in 10 lines.

Why GPS103 / TK103 still exists

  • Cheapest credible hardware · Coban's GPS103 reference is the entry point for fleet tracking · $8-$12 wholesale
  • Universal · 20+ OEMs clone the design; they all speak the same protocol
  • Simple · no binary parsing, no CRC, no length-prefix · plain text fits on a single line
  • Server-friendly · ASCII traffic is human-readable in raw TCP dumps, makes debugging trivial

It is not designed for CAN bus, fuel sensors, deep telemetry · those needs send you to Teltonika Codec 8 or Ruptela. For basic ignition + position + speed at the lowest possible cost, GPS103 wins on the price/feature curve.

Configuring a GPS103 / TK103 device for Traxelio

The SMS command set is universal across the family:

adminip123456 traxelio.com 5001
apn123456 internet                     (replace with your carrier's APN)
gprs123456                             (enable GPRS reporting)
fix030s***n123456                      (position every 30s when moving)

The 123456 is the default password · change it with password123456 NEWPASS.

Confirm the first decoded position in Traxelio. If the device doesn't connect, the order of operations matters · APN must be set BEFORE the device tries to open a data session.

Supported devices in our catalog

31+ devices declare protocol: "gps103" · the headline models: Coban GPS103, Coban TK103-2B, Coban 303F, Coban DualCam, plus many no-name clones. The TK303 family uses a closely-related but distinct packet shape · see the TK103 sub-page.

GPS103 vs TK103 vs H02

People conflate these three. Quick disambiguation:

  • GPS103 · the original Coban protocol · ASCII, semicolon-delimited, port typ. 9001/5001
  • TK103 · Coban's later revision · same family but slightly different packet shape, port typ. 5002
  • H02 · the Sinotrack / Cantrack / Secumore variant · ASCII but hash-delimited (*HQ,...#), port typ. 5013

All three are budget-tier ASCII protocols. Traxelio decodes all of them. The Traccar open-source server has three separate decoders for them · don't merge.

Setup walkthrough

  1. 1

    Insert SIM with data plan + airtime

    Test the SIM in a phone first · GPS103 devices have no UI to surface APN failures, so a dead SIM looks identical to a working one.

  2. 2

    Set the APN

    Send apn123456 your_carrier_apn to the device's SIM. APN must be set BEFORE the device tries to open a data session.

  3. 3

    Point the device at your server

    Send adminip123456 your-server.com 5001 to register the destination. Coban's reference port is 9001 and Traccar's is 5001 · use whatever your platform listens on.

  4. 4

    Enable GPRS reporting

    Send gprs123456 to enable the data session. Then fix030s***n123456 to report a position every 30s when moving.

  5. 5

    Change the default password

    Send password123456 NEWPASS to replace the factory 123456. Without this, anyone with the SIM phone number can re-point the device.

  6. 6

    Don't have a GPS103-compatible server yet?

    Traxelio decodes GPS103 / TK103 natively on port 5001. Send adminip123456 traxelio.com 5001 to the device and the first decoded position can be verified in Traxelio · LOAD acknowledgement handled automatically. Or self-host Traccar · same ASCII decoder.

Reference

Configuration reference

Parameter Value
Transport TCP
Default port 5001 (Traxelio) · 9001 (Coban ref) · 5002 (TK103 variant)
Encoding ASCII text, semicolon-delimited fields
Authentication Login packet `##,imei:NNNNNN,A;` · server replies `LOAD`
Heartbeat Configurable, default ~3min
SMS password default 123456 (change with `password123456 NEWPASS`)
Configurator SMS commands (no Windows tool needed for basic ops)
Spec PDF sourceforge.net/p/opengts/discussion/579835/thread/c0706b88/6fa0/4068/...

SMS commands

adminip123456 traxelio.com 5001

Set Traxelio as the device's server endpoint (`123456` is the default password).

apn123456 internet

Set the SIM's APN to your carrier's value (replace `internet`).

gprs123456

Enable GPRS data session · required before the device opens TCP to the server.

fix030s***n123456

Report a position every 30 s when moving (`fix060s` for 60 s, `fix120s` for 2 min, etc.).

check123456

Query GSM signal, GPS lock state, server connectivity · returns SMS reply with diagnostics.

stop123456

Engage engine-cut relay (only on Coban 303F / GPS103 with relay wired). `resume123456` releases.

password123456 NEWPASS

Change the SMS-command password from default `123456`. Do this on first deploy.

Or skip the integration

Traxelio decodes GPS103 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 GPS103 Devices

Traxelio processes all telemetry data sent by GPS103 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.

Recommended

Featured GPS103 Devices

Featured
Verified

Coban 303F

Coban
Featured
Verified

TK303G

Coban · $15 - $25
Featured

TK303B

Coban · $15 - $25
Featured

TKStar TK905

TKStar
Featured

TKStar TK915

TKStar

All Models

Representative GPS103 Devices (31)

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

306A

Coban

A306

Coban

Coban GPS106

Coban

Coban GPS107

Coban

Coban GPS301

Coban

Coban GPS302

Coban

Coban GPS303

Coban

Coban GPS304

Coban

Coban GPS305

Coban

Coban GPS306

Coban

GPS-103

Coban

GPS-103-A

Coban

Buy + activate today

GPS103 devices in our store

Ships from inventory · pre-configured for the Traxelio endpoint · arrives ready to install.

In store

Coban 303F

F CFA 25,000

Compatible Brands

Brands Using GPS103 Protocol

Coban

24 devices

TKStar

7 devices

Note: many manufacturers (Coban TK103, Sinocastel, Goome, and others) implement GPS103-compatible variants under their own protocol names. Check the relevant brand page to confirm compatibility before ordering.

Common troubleshooting

Device sends a single login packet then goes silent

Most common cause: server didn't reply LOAD (case-sensitive). The Coban firmware closes the TCP connection if it doesn't get the exact acknowledgement string within ~5 seconds. Confirm Traxelio's ingestor is sending LOAD\r\n. Less common: device firmware is too old and uses a different login format · capture the raw packet to see.

Positions arrive but timestamp is wrong (off by hours)

GPS103 timestamps are UTC by spec. If the device's RTC drifted (battery died, factory default reset), it may report local-time or 1980-01-01 epoch garbage. Send time123456 to sync the device clock to network time, or replace the backup battery if the drift comes back.

Engine-cut command sent but device ignores it

Two possibilities: (1) password mismatch · default 123456, but operators sometimes change it; the command must use the correct password. (2) relay variant of the device · plain GPS103 with no relay wiring has nothing to actuate. Confirm the device's hardware variant before assuming a software problem.

Explore More

Other Protocols

GT06

99 devices

H02

96 devices

Teltonika

84 devices

Meiligao

59 devices

GL200

36 devices

Huabao

32 devices
View All Trackers

FAQ

Frequently Asked Questions

Is GPS103 an open protocol?

Coban's spec PDFs leak across the integrator community freely · the protocol has been reverse-engineered and re-documented many times over the past 15 years. Traccar's GPS103 decoder is the most authoritative reference implementation. There is no licensing barrier to decoding it.

Why is the GPS103 / TK103 still in production after 15+ years?

Bottom-of-market position. The reference design is the cheapest credible 2G GPS tracker · entire markets (Latin America, Africa, South-East Asia) buy it because the next tier (Teltonika, Ruptela, Queclink) costs 5-10x more. The 2G sunset is killing the original GPS103 but Coban now ships 4G versions (Coban DualCam, Coban 303F-LTE) speaking the same ASCII protocol.

Does GPS103 work over 4G?

Yes on the newer Coban 4G hardware (Coban 303F-LTE, Coban DualCam). Same ASCII protocol, just transported over LTE Cat-1 or Cat-M1 modems instead of 2G GPRS. The protocol doesn't know or care which radio layer it rides on.

Can I run a GPS103 device alongside a Concox GT06 device on the same fleet?

Yes. They are different protocols but Traxelio decodes both. A mixed fleet (some Concox, some Coban) is common in budget-tier deployments · the dashboard sees them as the same kind of GPS event, the per-device protocol just changes how we parse the wire.

What's the difference between GPS103 protocol and the GPS103 device?

Same name, two meanings. GPS103 (device) is Coban's reference hardware sold under that name since ~2010. GPS103 (protocol) is the wire format Coban designed for that device, now also used by every clone and every newer Coban model in the same family. So a Coban 303F device speaks GPS103 protocol even though its model name is different.

Talk to integration team
T
Trax
Online
Say hello to Trax!