GPS Trackers

ATL100

Protocol

ATL100 Cold Chain Data Logger IoT Protocol

Revision 1.06 — Sep 21, 2025 — BLE scan settings (AT@BSS)

ATL100 Cold Chain Data Logger IoT Protocol R1.06 defines the data stream format, configuration commands, and message structures used between the ATL100 temperature data logger and backend server over CAT-M1 / NB-IoT / EGPRS. Use the sections below for a structured overview, or open the full PDF for complete command parameters and field definitions.

Revision history

Revision	Date	Description
1.00	2022-05-01	Initial release
1.01	2023-03-21	SACK Enable in AT@SIS; AT@ETS external temperature; temperature zone in +RPT and GCS Data Mask; RTO sub-commands 8/9; Sample RTC Time Mask in AT@CCS; PT100 and DS18B20 1-Wire in AT@ETS
1.02	2023-09-03	Optimized AT command structure; GNSS enable logic for motion / stillness
1.03	2024-04-10	eMTC and EGPRS network scan mode in AT@NIS; Sensor Data Number in +RPT
1.04	2025-03-16	Search No Signal Cover in AT@NIS; Button Working Mode in AT@GCS; AT@DOG software watchdog
1.05	2025-06-24	No Moving Send Interval in AT@RRS; regular report mode 2
1.06	2025-09-21	Added AT@BSS BLE scan settings command

Data stream format

Communication includes upstream (device → server) and downstream (server → device) data streams over the cellular network. Upstream carries responses to downlink commands and unsolicited reports. Downstream carries configuration, query commands, and responses to uplink messages.

Frame types

Direction	Encoding	Frame	Usage
Downstream	Printable ASCII	Configuration Command	Configure terminal parameters (AT@…=)
Downstream	Printable ASCII	Query Command	Query current parameters (AT@…?)
Downstream	Printable ASCII	+SACK	Server acknowledgement when the terminal sends a +RPT frame
Upstream	Printable ASCII	+QRY	Terminal response to a query command
Upstream	Printable ASCII	+ACK	Confirms a valid configuration command was received
Upstream	Hexadecimal	+RPT / -RPT	Real-time and buffered report messages

All upstream and downstream frames end with the character "#" (0x23). In printable ASCII frames, "," separates adjacent parameters. Hexadecimal frames have no parameter separator.

Configuration commands

Configuration commands use the format AT@<KEY>=<password>,<parameters>,…,<serial># . Each command is protected by a password (default bcc100) and ends with a 4-digit hexadecimal serial number and "#".

Example — main server settings:

AT@SIS=bcc100,0,1,255.255.255.255,12345,,,0,0001#

Network commands

Code	Command	Description
SIS	AT@SIS=	Main server IP, port, report mode (0 Stop / 1 TCP / 2 UDP), buffer mode, SACK enable
NIS	AT@NIS=	APN, credentials, network scan mode (0 auto, 1 EGPRS, 2 NB-IoT, 3 eMTC, 4 eMTC+NB2, 5 eMTC+EGPRS), Search No Signal Cover

General commands

Code	Command	Description
GMT	AT@GMT=	Greenwich Mean Time / time zone setting
GCS	AT@GCS=	Global configuration: +RPT Data Mask, LED mode, GNSS mode, GNSS Info Mask, power saving, power-on mode, button working mode
RRS	AT@RRS=	Regular report: mode (0 off / 1 mode1 / 2 mode2), sensor sample interval, send interval, no-moving send interval

Cold chain commands

Code	Command	Description
CCS	AT@CCS=	Cold chain settings: Cold Chain Info Mask, tilt, flight mode, motion/stillness, crash, light, built-in temperature/humidity alarms
ETS	AT@ETS=	External temperature sensors (PT100, DS18B20 1-Wire) alarm thresholds and duration

Operations, OTA, and BLE

Code	Command	Description
RTO	AT@RTO=	Real-time operation (reboot, power off, quick server debug, delete buffer messages, and more)
DOG	AT@DOG=	Software watchdog: mode and interval
UPF	AT@UPF=	Firmware upgrade over the air
BMS	AT@BMS=	Device management system: BMS server, report interval, +BMR Data Mask
BSS	AT@BSS=	BLE scan settings (added in v1.06)

Report mode (SIS/BMS): 0 = Stop, 1 = TCP, 2 = UDP. Buffer mode: 0 = disabled, 1 = low priority, 2 = high priority. When buffer is enabled and the device loses coverage or does not receive +SACK, reports are stored locally and sent when connectivity returns.

Query commands

Query commands retrieve the current working parameters of the terminal. They use printable ASCII with comma-separated fields:

AT@<KEY>?<password>,,<serial>#

AT@SIS?bcc100,,# — query main server settings
AT@NIS?bcc100,,# — query network (APN) settings
AT@GMT?bcc100,,# — query time settings
AT@GCS?bcc100,,# — query global configuration
AT@RRS?bcc100,,# — query regular report settings
AT@CCS?bcc100,,# — query cold chain settings

When sent by the backend server, parameters are returned to the server. When sent by SMS, parameters are returned via SMS.

Message format

Report messages share a common frame structure with header, data, and tail zones:

Zone	Fields	Encoding
Header	Head (5 B) + Length (2 B) + IMEI (8 B) + Device ID (1 B)	ASCII / HEX / HEX / HEX
Data	Variable payload + G-time (7 B)	HEX or ASCII
Tail	Serial number (2 B) + Tail "#" (1 B)	HEX / ASCII

+RPT / -RPT and +BMR / -BMR — data zone encoded in hexadecimal (big-endian for multi-byte values)
+SACK — fully ASCII encoded
+ACK, +QRY, +ALL, +QNI, +VER — data zone in ASCII with comma separators

Report messages (+RPT / -RPT)

+RPT frames are real-time reports generated and sent within 3 minutes. -RPT frames are historical reports stored in the device buffer and sent when connectivity is restored.

All event-driven and regular reports share the same +RPT/-RPT hex-encoded format. The Data Mask in AT@GCS controls which information zones are included in each report.

Key +RPT Data Mask bits (AT@GCS)

Bit	Field	Content
0	Multi-packet	Frame count and frame ID
1	Network type	Cellular network type
2	Battery	Voltage (mV) and level (%)
3	GNSS information	Fix type, HDOP, speed, azimuth, altitude, lat/lon, UTC time
4	Cell information	MCC, MNC, LAC, Cell ID, CSQ
5	Neighboring cell	Adjacent cell information
6	Cold chain information	Temperature, humidity, light, motion, 1-Wire sensors
7	Upgrade information	Firmware upgrade status
19	BLE information	BLE scan results

Event types

Type	Event
0	Terminal power
1	Regular report
2	Moving
3	Battery alarm
4	Free fall alarm
5	Tilt alarm
6	Flight mode
7	Crash alarm
8	Light alarm
9	Built-in temperature alarm
10	Humidity alarm
11	Upgrade firmware
12	External temperature alarm
30	BLE common info

The full PDF lists every event state, Cold Chain Info Mask bit, sensor data field, and byte length with value ranges.

Buffer messages (+BMR / -BMR)

+BMR frames are real-time BMS reports generated and sent within 3 minutes. -BMR frames are buffered BMS reports sent when connectivity is restored. Configure BMS reporting via AT@BMS.

Parameter	Description
Report Mode	0 = Stop, 1 = TCP
Buffer Mode	0 = disabled, 1 = enabled
BMS Server IP / Port	Device management server address
Connection Life	0 or 5–300 seconds
Report Interval	1–2880 minutes
BMR Data Mask	Component mask for +BMR/-BMR message content (set via AT@BMS)

+BMR/-BMR use the same header/tail frame structure as +RPT/-RPT with a hexadecimal data zone.

Acknowledgement

Frame	Direction	Description
+ACK	Device → server	Confirms a valid configuration command was received
+SACK	Server → device	Server acknowledgement when SACK Enable is set in AT@SIS

Command query responses

Frame	Description
+QRY	Response to a single query command
+ALL	Bulk response with all configured parameters
+QNI	Network information query response (APN, IMSI, ICCID, CSQ, cell ID)
+VER	Firmware and hardware version information

Terms and abbreviations

Term	Meaning
ACK	Acknowledgement
APN	Access Point Name
BLE	Bluetooth Low Energy
CCS	Cold Chain Setting
EGPRS	Enhanced General Packet Radio Service
G-Time	Generated Time
GNSS	Global Navigation Satellite System
IMEI	International Mobile Equipment Identity
IoT	Internet of Things
NB-IoT	Narrowband IoT
RPT	Report message
SACK	Server acknowledgement
TCP / UDP	Transmission Control / User Datagram Protocol
UTC	Coordinated Universal Time

In this document, "terminal", "device", and "equipment" refer to the ATL100 cold chain data logger unless otherwise specified.

ATL100 — Protocol

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v1.06 · 2025-09-21 · Release

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