Appearance
Y201-W Mini WiFi DTU Technical Manual
Table of Contents
- Introduction
- System Overview
- Hardware Interfaces
- Electrical Specifications
- Serial Configuration & Packaging
- WiFi Networking & Web Console
- Socket Protocol Workflows
- Modbus Gateway & JSON Services
- Advanced Functions
- Remote Management & Diagnostics
- AT Command Highlights
1. Introduction
Y201-W is the WiFi-enabled member of the MiniLink Y201 DTU family. It keeps the compact 74.6 × 22.6 × 18.1 mm enclosure while adding 2.4 GHz WLAN uplink (AP/STA/AP+STA) and retaining a single selectable serial interface (RS485 / RS232 / TTL). Dual sockets (A/B) per UART support TCP/UDP/HTTP/MQTT/EDP, Modbus RTU ↔ TCP gateway, registration packets, heartbeats, JSON uploader, remote AT, and HTTP OTA upgrades—matching the firmware capabilities of Y201-R/Y202-W so mixed fleets share identical workflows.
| Item | Description |
|---|---|
| MCU & OS | Dual-core 240 MHz MCU + RTOS, hardware + software watchdog |
| Serial Interface | One configurable RS485/RS232/3.3 V TTL port |
| Wireless | 802.11 b/g/n (2.4 GHz) AP / STA / AP+STA |
| Power | 5–36 V DC via 2-pin terminal |
| Services | TCP/UDP/HTTP/MQTT/EDP, Modbus gateway, JSON uploader, OTA |
Mechanical, ordering, and SKU details are documented in the Y201-W Specification.
2. System Overview
- Architecture – Industrial MCU with RTOS, dual watchdog, and programmable reboot-on-silence.
- Serial Port – Single UART mapped to RS485/RS232/TTL terminals; firmware setting chooses the active interface while Socket A/B share the same stream.
- Wireless Stack – Integrated 2.4 GHz radio with AP (default
W100), STA for router uplink, or AP+STA for maintenance + backend simultaneously. - Web Console – Embedded HTTP UI (Status/System/Port) at
192.168.4.1(AP) mirrors AT commands for IP, WiFi, serial, socket, Modbus, and OTA settings. - Use Cases – Retrofits lacking RJ45 cabling, portable testers, and sensor gateways needing WiFi-only connectivity while keeping wiring footprint minimal.
3. Hardware Interfaces
| Group | Description |
|---|---|
| Power | 2-pin terminal (V+, V-) accepting 5–36 V DC; reverse-polarity guarded. |
| Serial | Shared pins labeled RS485 A/B, RS232 TX/RX/GND, TTL TX/RX/GND. Only the ordered interface is populated; wiring must respect the label on the shell. |
| WiFi | SMA female antenna connector (use supplied whip). |
| USB | Micro-USB (CDC) for local AT console and firmware loading. |
| Button | Reload – hold 3–5 s to restore last saved profile, >5 s for factory defaults. |
| QR Label | Encodes SN + MAC for quick onboarding. |
LED Behavior
| LED | Behavior | Meaning |
|---|---|---|
| POWER | Steady on | DC supply OK |
| WORK | Slow blink (~1 s) | WiFi connected (STA) / AP broadcasting |
| WORK | Fast blink (~300 ms) | WiFi disconnected or searching |
| TX | Blink | Serial TX (network→serial data) |
| RX | Blink | Serial RX (serial→network data) |
Always install the antenna before powering on to avoid PA damage and guarantee coverage.
4. Electrical Specifications
| Parameter | Value |
|---|---|
| Supply Voltage | 5–36 V DC |
| Typical Current | 60 mA @ 12 V (WiFi idle, single socket) |
| Startup Current | ≥600 mA required momentarily when using 5 V supplies |
| Operating Temp | -35 °C ~ +75 °C (extended -40 °C ~ +85 °C) |
| Humidity | 5% ~ 95% RH, non-condensing |
| Protection | Reverse polarity, surge clamp, watchdog reset |
Recommendation: avoid powering from unstable USB ports; use regulated DC supply or dedicated adapter.
5. Serial Configuration & Packaging
5.1 UART Parameters
Command: AT+UART=<baud>,<databits>,<stopbits>,<parity>,<fc>
| Field | Options | Default |
|---|---|---|
| Baud Rate | 1,200–460,800 bps | 115,200 |
| Data Bits | 7 / 8 | 8 |
| Stop Bits | 1 / 2 | 1 |
| Parity | NONE / EVEN / ODD | NONE |
| Flow Control | NFC (RS232) / 485 (auto-direction) | NFC |
5.2 Packaging (AT+UARTTL)
- Length trigger: 64–1024 bytes (default 1024).
- Gap trigger: 0–300 ms (default 0 = adaptive).
- Either threshold flushes data toward both sockets simultaneously. Example:
AT+UARTTL=30,512.
5.3 Modes
- Transparent Mode – Default data tunnel.
- AT Command Mode – Send
+++, wait ≥500 ms, thena. Exit withAT+EXITor reboot; sockets pause ≤3 s. - Remote AT – Enable via
AT+EXAT=<mode>,<keyword>to accept AT commands over sockets once LAN discovery authenticates.
Match UART settings with the downstream device before wiring; mismatched baud/format can prevent WiFi provisioning per the Chinese quick guide.
6. WiFi Networking & Web Console
6.1 Default AP Mode
| Parameter | Value |
|---|---|
| SSID | W100 (broadcast) |
| Security | Open by default (change to WPA2/WPA3 immediately) |
| IP | 192.168.4.1 |
| DHCP | Enabled (1–6 clients) |
| HTTP Login | admin / admin |
Steps:
- Power on, connect a laptop/phone to SSID
W100. - Browse to
http://192.168.4.1, log in, and change WiFi security (recommended). - Configure serial, sockets, Modbus gateway, and WiFi STA parameters if needed.
- Save → Reboot → reconnect serial device.
6.2 STA & AP+STA
AT+NETIF=STAto join routers (2.4 GHz only); useAT+STA=<ssid>,<password>or set password toNONEfor open APs.AT+NETIF=APSTAkeeps AP available while STA uplinks; note performance impact and ensure AP/STA IP ranges differ.- After switching to STA, use the WAN IP (DHCP or static) to reach the web UI or issue AT commands via remote AT.
- Query STA state using
AT+STALK; change AP channel viaAT+WCH=<1-13>when acting as AP.
6.3 LAN Discovery & Virtual COM
- UDP broadcast search:
AT+SEARCH=8168,HuayunIOT(PC tool sends query and devices reply withIP,MAC,MODEL,VER). - Virtual COM helper replicates COM ports over TCP for legacy PC software; ensure Windows driver signature enforcement is disabled if installation fails (BIOS Secure Boot OFF +
bcdedit /set nointegritychecks on).
7. Socket Protocol Workflows
Since Y201-W has one UART, Socket A and Socket B share the same serial stream. Enable with AT+SOCKENs=ON (s = A/B) and configure via AT+SOCKs=<type>,<addr>,<port>[,localport].
7.1 TCP Server / Client
- Server: listens on default port 8010; supports up to 8 clients. Example:
AT+SOCKENA=ON AT+SOCKA=TCPS,0.0.0.0,8010 AT+REBOOT - Client: auto-reconnect every second. Example:
AT+SOCKENB=ON AT+SOCKB=TCPC,10.10.10.50,9000 AT+REBOOT
7.2 UDP Modes
UDPCtargets fixed IP/port; setlocalportif firewalls expect a known source.UDPSreplies to the most recent sender—ideal for handheld maintenance apps.
7.3 HTTP Client
- Switch to
HTPC. - Configure headers (
AT+HTPHD=Connection:keep-alive|Content-Type:application/json). - Choose mode:
AT+HTPREQ=GET/POST/AUTO. - For POST, set
AT+HTPURL=/api/v1/upload; for AUTO, embed URL + payload separated by\r\n. - Heartbeats can trigger HTTP GET by setting NET heartbeat payload to the URL.
7.4 MQTT Client
AT+MQCONFn=<type>,<addr>,<port>for broker info (supports Aliyun shortcut).AT+MQAUTHn=<user>,<password>for credentials.AT+MQPUBn,AT+MQSUBndefine topics and QoS (0/1/2).- Device behaves like a transparent tunnel: UART payloads map to publish frames, subscribed topics map back to UART.
7.5 Registration Packets & Heartbeats
- Registration:
AT+REGTP=MAC/CUS,AT+REGMD=OFF/FIRST/EVERY/ALL,AT+REGDAT=<hex>. - Heartbeats:
AT+HEARTMD=NET/UART,AT+HEARTTM=<seconds>,AT+HEARTDAT=<hex>. - NET heartbeats support TCP/UDP Client; UART heartbeats trigger serial polls even when network is idle.
7.6 Peer-to-Peer (EDP)
- Configure
AT+SOCKA=EDP,huayuniot,888and assign peer ID usingAT+EDP=<target_id>,OFF. - Supports one-to-one, one-to-many, or many-to-one without additional servers (IDs obtained from Yanji support).
8. Modbus Gateway & JSON Services
- Enable gateway with
AT+MBMD=ON(or Port tab). Ethernet-side Modbus TCP converts to RTU on the serial bus; disable when running pure transparent sockets. - Polling scheduler:
AT+MBCFG=ON,200,5 # 200 ms interval, report every 5 s AT+MBCMD=010300000002C40B - JSON uploader:Payloads can be sent via HTTP (HTPC) or MQTT sockets. Error handling controlled by
AT+HJREG=loop_current,40001,U16,0.1,A AT+MBJS=ON,30AT+JSERR.
9. Advanced Functions
| Feature | Command | Description |
|---|---|---|
| Offline Cache | AT+CACHE=ON/OFF | Stores up to 50 frames (~20 KB) when WiFi drops; auto-flush on recovery. |
| Data Conversion | AT+DTCVT=<uplink>,<downlink> | Converts RAW↔HEX or custom formats per direction. |
| No-Data Reboot | AT+SOCKRTO=<minutes> | Reboots after prolonged inactivity (default 1440 min, 0 disables). |
| HTTP OTA | AT+DOWNLOAD=<host:port/path> | Downloads firmware over HTTP; reboot to apply. |
| Backup/Restore | AT+BKCFG, AT+RSTCFG, AT+CLRCFG | Snapshot, reload, or factory reset. |
| WiFi Scan | AT+SCAN | Lists nearby SSID/RSSI/auth types for siting. |
| AP Client List | AT+APLK | Displays STA MAC + RSSI when acting as AP. |
10. Remote Management & Diagnostics
- Commissioning Flow – Wire power only, configure WiFi + serial via AP, then connect the serial device after UART parameters match.
- Registration & Heartbeats – Enable FIRST registration packets so backend systems log MAC/SN at every connect; set NET heartbeat (60 s typical) to detect WiFi drops.
- Auto-Recovery – Configure
AT+SOCKRTO=30(minutes) plus watchdog so the DTU reboots if no data arrives for extended periods. - Firmware Maintenance – Host firmware on HTTP server and trigger
AT+DOWNLOAD=host:port/file.bin; schedule upgrades during maintenance windows. - LAN Discovery – Use UDP search or remote AT to audit devices without physical access; credential prompts protect remote AT sessions.
- Troubleshooting –
AT+DEVINFO– model, firmware, MAC, SN.AT+SOCKLK– reports socket states (ON/OFF, peer IP).AT+PING=<host>– verifies WAN reachability.AT+NETSTAT– displays interface (AP/STA) statistics.AT+LOG=<level>– temporary debug verbosity.- Reload button – quick restore of last saved config without PC.
11. AT Command Highlights
| Command | Purpose |
|---|---|
AT+LIST | Display supported AT commands |
AT+VER | Firmware version |
AT+NETIF | Select AP / STA / AP+STA |
AT+AP, AT+STA, AT+WCH, AT+NUMSTA | WiFi SSID/password/channel/STA limit |
AT+LAN, AT+WAN, AT+DNS, AT+SEARCH | AP IP, STA IP/DNS, discovery keyword/port |
AT+UART, AT+UARTTL | Serial parameters & packaging |
AT+SOCKs, AT+SOCKENs | Socket definition/enabling (s = A/B) |
AT+REGTP, AT+REGMD, AT+REGDAT | Registration packet type/mode/payload |
AT+HEARTMD, AT+HEARTTM, AT+HEARTDAT | Heartbeat mode/interval/data |
AT+MBCFG, AT+MBCMD, AT+MBJS, AT+HJREG | Modbus polling and JSON mapping |
AT+MQCONFn, AT+MQAUTHn, AT+MQPUBn, AT+MQSUBn | MQTT configuration |
AT+HTPURL, AT+HTPHD, AT+HTPREQ, AT+HTPFT | HTTP client settings |
AT+EDP | Peer-to-peer ID targeting |
AT+CACHE, AT+SOCKRTO, AT+DOWNLOAD | Cache, auto-reboot, OTA |
AT+BKCFG, AT+RSTCFG, AT+CLRCFG | Backup/restore/factory reset |
- Linked Documents: Y201-W Specification · Y201 Series Overview
- Manufacturer: Hunan Yanji Tech Co.,Ltd · Email: hi@yanjiiot.com