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Y201-G Mini 4G DTU Technical Manual
Table of Contents
- Introduction
- System Overview
- Hardware Interfaces
- Electrical Specifications
- Serial Configuration & Packaging
- Cellular Networking & Data Transmission
- Modbus Polling & JSON Reporting
- Advanced Functions
- Remote Management & Diagnostics
- AT Command Highlights
1. Introduction
Y201-G is the MiniLink Series 4G LTE member of the Y201 mini DTU family. It targets cabinets and edge panels that need cellular backhaul without changing existing RS485/RS232 wiring, delivering Cat1 LTE connectivity, SIM lifecycle management, and remote diagnostics inside a palm-sized DTU. With built-in TCP/UDP/HTTP/MQTT channels, MiniLink Y201-G moves factory, power, and environmental telemetry to cloud platforms even in harsh, power-constrained cabinets.
| Item | Description |
|---|---|
| MCU & OS | Industrial MCU with real-time task scheduler and hardware watchdog |
| Serial Interfaces | RS485 (2-pin), RS232 (3-pin), TTL (3-pin), selectable |
| Cellular Uplink | LTE Cat1 full-netcom with integrated SIM tray |
| Dimensions | 74.6 × 22.6 × 18.1 mm (without ears/antenna base) |
| Mounting | DIN-rail clip or panel mounting ears |
Positioning Highlights
- Palm-sized cellular DTU gateway for power, building automation, environmental monitoring, and OEM controller retrofits
- Provides 4 concurrent socket pipelines for redundant or multi-host connectivity over LTE networks
- Built-in Modbus polling and JSON reporting reduce SCADA workload and bandwidth consumption
2. System Overview
- Architecture: Industrial MCU + RTOS scheduler; hardware watchdog + software exception handling for continuous uptime.
- Serial Access: Shared UART routed to pluggable RS485 (2-pin), RS232 (3-pin), or TTL (3-pin) headers. Only one interface is active at a time and can be switched via firmware.
- Cellular Stack: Cat1 LTE modem supporting LTE-FDD B1/B3/B5/B8 and LTE-TDD B34/B38/B39/B40/B41 with automatic network registration, APN selection, and SIM status detection.
- Firmware Services: Multi-socket manager, HTTP client engine (GET/POST/AUTO modes), MQTT publish/subscribe including Aliyun-compatible auth, Modbus polling with JSON rendering, ASCII/HEX converters, remote upgrade routines.
- Indicators: POWER LED (steady = powered), WORK LED (fast blink before network attach, slow blink after attach), DATA LED (off = server disconnected, on = connected, blink = data traffic).
3. Hardware Interfaces
3.1 Power & Connectors
| Group | Description |
|---|---|
| Power | 5-pin pluggable terminal (2.54 mm). Pins: V+, V- (9~36 VDC), plus RS485 A/B or RS232 TX/RX depending on SKU. Reverse-polarity protected. |
| Cellular | Nano-SIM slot with card-detect + SMA antenna connector for LTE whip/patch antenna. |
| Serial | RS485: 2-pin (A/B); RS232: 3-pin (TX/RX/GND); TTL: 3.3 V (TXD/RXD/GND). |
| USB | Micro-USB for local firmware upgrade (driver required). |
| Button | Reload: Press 3–10 s to restore last saved parameters (equivalent to AT+RSTCFG). |
3.2 LED Behavior
| LED | State | Meaning |
|---|---|---|
| POWER | Steady on | Power OK |
| WORK | Fast blink (≈400 ms) | LTE module booting / searching for base station |
| WORK | Slow blink (≈2 s) | Registered to network |
| DATA | Off | No active socket |
| DATA | Steady on | Socket connected |
| DATA | Blinking | Serial/network data exchanging |
4. Electrical Specifications
| Parameter | Value |
|---|---|
| Dimensions | 74.6 × 22.6 × 18.1 mm (excluding mounting ears/terminal) |
| Weight | 35 g (typical) |
| Supply Voltage | 9~36 VDC |
| Typical Current | 100 mA @ 12 V (idle) |
| Operating Temp | -35 °C ~ +75 °C (standard), -40 °C ~ +85 °C (extended) |
| Humidity | 5% ~ 95% RH, non-condensing |
| Protection | Reverse polarity, EFT/ESD up to IEC 61000-4-2 Level 4 |
| Mounting | DIN rail clip or dual-ear screw mounting |
Clearance recommendation: keep ≥10 mm around the shell for heat dissipation and allow ≥50 mm front access for wiring.
5. Serial Configuration & Packaging
5.1 UART Parameters
AT+UARTn=<baud>,<databits>,<stopbits>,<parity>,<flow>
| Field | Options |
|---|---|
| Baud Rate | 1200~460800 bps (default 115200) |
| Data Bits | 8 (default) or 7 |
| Stop Bits | 1 (default) or 2 |
| Parity | NONE (default) / EVEN / ODD |
| Flow Control | NFC (no flow control) or 485 (auto-direction) |
5.2 Data Packaging
AT+UARTTLn=<interval_ms>,<length_bytes>
- Length trigger: frame forwarded once it reaches
length(64–1024 bytes, default 1024). - Gap trigger: frame forwarded when inter-character gap ≥
interval(1–300 ms, default 5 ms). - TCP stream users should implement application-level delimiters because of unavoidable packet coalescing.
5.3 UART Modes
- Transparent Mode (default): Serial payload forwarded directly to active sockets.
- AT Command Mode: Enter by sending
++++ delay +a; exit viaAT+EXITor reboot. Network data pauses up to 3 s after+++to prevent interference.
6. Cellular Networking & Data Transmission
6.1 Socket Channels
- Up to 4 sockets (A/B/C/D) per serial channel. Configure via
AT+SOCKns=<type>,<addr>,<port>and enable withAT+SOCKENns=ON. - Supported types:
TCPC,UDPC,HTPC(HTTP client),MQTT. - Keepalive and reconnect behaviors are built-in; failed TCP dial attempts back off up to 60 s.
6.2 TCP Client Workflow
- Insert SIM, connect antenna, power on, and wait for WORK LED slow blink.
- Set socket type to
TCPCwith target host/port. - Configure APN if needed via
AT+APN=1,<apn>,<user>,<pass>,<auth>. - Save + reboot (or
AT+REBOOT). Device auto-connects and mirrors serial data bidirectionally.
6.3 UDP Client Workflow
- Works peer-to-peer with fixed remote IP/port.
- Local source port is random; remote must echo a packet before it knows the port number.
6.4 HTTP Client
- Modes:
GET,POST,AUTO(URI-driven). Configure base parameters withAT+HTPURLn,AT+HTPHDn,AT+HTPREQn. - AUTO mode allows on-the-fly URI + payload separation using
\r\nbetween URL and data. - Timeout configurable via
AT+HTPTOn(1–30 s, default 6 s).
6.5 MQTT
- Authentication via
AT+MQAUTHn=<clientID>,<user>,<pass>. - Connection profile:
AT+MQCONFn=<version>,<clean>,<keepalive>. - Publish/subscribe topics set with
AT+MQPUBnandAT+MQSUBn(QoS0/1/2 supported). - Aliyun shortcut mode available:
AT+MQMDn=ALIauto-generates signatures.
6.6 Modbus TCP/RTU Gateway
AT+MODBUSn=ON converts incoming Modbus TCP into RTU frames (and vice versa). Non-Modbus packets are dropped to protect fieldbus integrity.
7. Modbus Polling & JSON Reporting
7.1 Polling Scheduler
- Enable scheduler with
AT+MBCFGn=<enable>,<interval_ms>,<period_s>. - Upload commands via
AT+MBCMDn=<hex_cmd>|<hex_cmd2>|...(total ≤240 bytes).
7.2 JSON Mapping
- Mode selection:
AT+MBJSn=<mode>,<interval_s>OFF: disabledPOLL: only upload Modbus data (serial transparent mode disabled)ALL: upload Modbus + allow pass-through
- Define datapoints using
AT+HJREGJSON arrays (factor,dev_id,fun,reg,type,multiple). - Optional fields:
- Device IMEI/ICCID via
AT+JSIMEIn,AT+JSICCIDn - Timestamp formatting (
UNIX,UTC,LOCAL) viaAT+JSTMn - IO snapshot, GPS placeholders (hardware dependent)
- Device IMEI/ICCID via
- Error handling:
AT+JSERRn=ONpushesnullwhen polling fails;OFFpushes zero.
7.3 Uplink Payload Example
json
{
"imei": "860061060041515",
"time": 1681105255,
"data": {
"k1": 12.3,
"k2": null,
"k3": 666
}
}(Actual keys follow user-defined factor names.)
8. Advanced Functions
| Feature | Command | Description |
|---|---|---|
| Offline Cache | AT+CACHEn=ON/OFF | Stores up to 50 frames (≈20 KB). Buffered data flushes automatically when link recovers. |
| Data Format Conversion | AT+DTCVTn=<uplink_mode>,<downlink_mode> | Convert RAW↔ASCII HEX for serial/network directions independently. |
| Enhanced AT (透传AT) | AT+EXAT=<mode>,<keyword> | Accept AT commands over serial, network, or SMS streams using trigger keyword (default NAT@). |
| Base Station Location | AT+LBS returns CID/LAC for approximate positioning via third-party services. | |
| Offline Cache to Cloud | Combine AT+CACHEn with Modbus JSON to resend buffered data when LTE reconnects. | |
| Firmware Upgrade (USB) | Use Micro-USB + vendor driver; behaves like CDC COM port for DFU utility. | |
| Firmware Upgrade (HTTP) | AT+DOWNLOAD=<host:port/path> downloads firmware via HTTP; device reboots automatically after success. |
9. Remote Management & Diagnostics
9.1 Heartbeat & Registration Packets
- Heartbeat mode:
AT+HEARTMDn=UART/NET, interval viaAT+HEARTTMn(1–86400 s). Payload defined byAT+HEARTDATn=<data>,<fmt>. - Registration packets: type via
AT+REGTPn=IMEI/ICCID/USER, send mode viaAT+REGMDn=FIRST/EVERY/ALL, and custom payload viaAT+REGDATn.
9.2 Remote Device Management
- Enable service with
AT+RDM=ONto allow centralized status monitor.
9.3 Exception Handling
- No-data watchdog:
AT+SOCKRTO=<minutes>(0 disables, default 1440). Device reboots if no network data is received within the window. - Reload button or
AT+RSTCFGrestores backed-up parameters;AT+CLRCFGreverts to factory defaults, whileAT+BKCFGsaves current runtime settings as the new backup.
9.4 Diagnostics
AT+DEVINFOreports module, firmware, MAC, manufacturing info.AT+SOCKLKdisplays per-socket connection state.AT+PING=<host>assists in verifying network reachability.
10. AT Command Reference
This section mirrors the "3.1 AT指令" chapter of the Chinese manual, summarizing syntax, error codes, and major commands in tabular form. Commands follow the standard query (AT+CMD?), set (AT+CMD=value), and help (AT+CMD=?) patterns and accept CR/LF line endings. Single-line commands can be up to 256 bytes and must wait for the previous response before issuing the next one.
10.1 Error Codes
| Error Code | Meaning | Typical Cause |
|---|---|---|
ARGS | Invalid argument | Value out of range / bad format |
ARGC | Invalid argument count | Missing or extra parameters |
CMD_UNKNOWN | Unknown command | Misspelled or unsupported command |
CMD_FORMAT | Bad format | Not prefixed with AT+ |
CMD_LENGTH | Exceeds max length | Payload >256 bytes |
DEV_MEMORY | Memory error | Internal buffer issue |
DEV_SAVE | Save failed | Flash write error |
10.2 Frequently Used Commands
| Command | Purpose | Key Parameters / Notes |
|---|---|---|
AT+LIST | List supported commands | Returns +LIST:AT+CMD lines |
AT+EXIT | Leave AT mode → transparent | Responds OK then resumes data mode |
AT+VER | Query firmware version | Returns +VER:<ver> |
AT+DEVINFO | Device info (model, version, IMEI, SN, etc.) | Multiple +FIELD:<value> lines |
AT+REBOOT | Soft reboot | No parameters |
AT+RSTCFG / AT+BKCFG / AT+CLRCFG | Restore backup / save backup / factory reset | Manage parameter partitions |
AT+RDM=<state> | Remote device management enable | ON/OFF (default OFF) |
AT+DOWNLOAD=<uri> | HTTP firmware download | URI such as host:port/file.bin; responds OK or +ERROR:FAIL |
10.3 Networking & Diagnostics
| Command | Purpose | Notes |
|---|---|---|
AT+SOCKENns=<state> | Enable/disable socket A/B for UART n | Default enables SOCK1A only |
AT+SOCKns=<type>,<addr>,<port> | Configure socket protocol & endpoint | Types: TCPC, UDPC, HTPC, EDP, SMS, MQTT |
AT+SOCKLK[=ns] | Query TCP client link status | Reports ON/OFF per socket |
AT+APN=<mode>,<apn>,<user>,<pass>,<auth> | Custom APN/VPDN | mode=0 use default; auth = 0/1/2 (NONE/PAP/CHAP) |
AT+CSQ / AT+CEREG / AT+CGATT | Signal, registration, data attach | Report RSSI, network attach state |
AT+IP | Query current IP address | Returns IPv4 string |
AT+IMEI / AT+ICCID / AT+IMSI | SIM identifiers | 15/20/15-digit strings |
AT+PING=<host> | Connectivity test | Returns latency or error cause |
AT+HEARTMDn / AT+HEARTTMn / AT+HEARTDATn | Heartbeat mode, interval, payload | Modes: OFF/NET/UART |
AT+REGTPn / AT+REGMDn / AT+REGDATn | Registration packet type/mode/payload | Types: IMEI/ICCID/USER; modes: OFF/FIRST/EVERY/ALL |
AT+SOCKRTO=<minutes> | Reboot on no data | 0 disables; default 1440 min |
10.4 Serial & Data Handling
| Command | Purpose | Key Parameters |
|---|---|---|
AT+UARTn=<baud>,<databits>,<stopbits>,<parity>,<flow> | Configure UART n | Baud options 1200–460800; parity NONE/EVEN/ODD; flow NFC/485 |
AT+UARTTLn=<interval>,<length> | Set UART packing | Interval 1–300 ms; length 64–1024 bytes |
AT+CACHEn=<state> | Offline cache ON/OFF | Stores up to 50 frames (≈20 KB) |
AT+DTCVTn=<uplink_mode>,<downlink_mode> | ASCII/HEX conversion | RAW/BTS/STB per direction |
AT+EXAT=<mode>,<keyword> | Enhanced AT keyword | Modes OFF/NET/UART/ALL; default keyword NAT@ |
10.5 HTTP / MQTT / Cloud
| Command | Purpose | Notes |
|---|---|---|
AT+HTPREQn / AT+HTPURLn / AT+HTPHDn / AT+HTPTOn | HTTP method, URL, headers, timeout | Supports GET/POST/AUTO; headers separated by ` |
AT+MQCONFn / AT+MQAUTHn / AT+MQSUBn / AT+MQPUBn / AT+MQWILLn | MQTT connect/auth/subscribe/publish/will | QoS 0/1/2, retain flag, keepalive 30–65535 s |
AT+MQMDn=ALI | Aliyun MQTT shortcut | Auto-calculates auth fields |
AT+EDPn=<id_list>,<save> | Point-to-point binding | IDs separated by ` |
AT+MODBUSn=<enable> | Modbus TCP/RTU conversion | Drops packets when disabled |
AT+MBCFGn, AT+MBCMDn, AT+MBJSn, AT+HJREG | Modbus polling & JSON mapping | Matches Section 7 descriptions |
10.6 JSON & Auxiliary Fields
| Command | Purpose | Notes |
|---|---|---|
AT+JSERRn=<mode> | Report null or 0 on read failure | ON = null, OFF = 0 |
AT+JSUDn=<en>,<key>,<val> | Custom JSON key/value | Up to 64 bytes each |
AT+JSTMn=<en>,<key>,<fmt> | Timestamp field (UNIX/UTC/LOCAL) | Format strings match PDF examples |
AT+JSIMEIn, AT+JSICCIDn, AT+JSIOn, AT+JSGPSn | Include IMEI, ICCID, IO status, GPS fields | GPS formats: JSON / RMC |
- Manufacturer: Hunan Yanji Tech Co.,Ltd
- Address: Room 21014, Unit 1, Fudixingguang plaza, Yuhua district Yingxin road, Changsha, Hunan, P.R. China
- Email: hi@yanjiiot.com
- Website: www.yanjiiot.com