YenGear

Appearance

Y201-G Technical Manual ​

Y201-G

Y201-G Specification

Contents ​

  1. Overview
  2. Default Parameters
  3. Serial Modes and Packetization
  4. Data Transfer and Sockets
  5. AT Command Conventions
  6. AT Command Quick Reference
  7. Modbus Polling and JSON Reporting
  8. Maintenance, Upgrade, and Exception Handling
  9. Troubleshooting

1. Overview ​

Y201-G, corresponding to the vendor model EP-D200, is used for remote communication between serial devices and a 4G Cat.1 network. It supports TCP, UDP, HTTP, MQTT, peer-to-peer transmission, SMS transparent transmission, serial or network or SMS AT commands, and Modbus polling with JSON reporting.

ItemDescription
Uplink4G Cat.1
Serial InterfaceRS232 / RS485 / TTL, depending on SKU
Socket ChannelsMulti-channel support per serial port, Socket A enabled by default
Maintenance MethodsConfig tool, serial AT, network AT, SMS AT

2. Default Parameters ​

The following defaults come from the vendor AT command and function documentation.

ParameterDefault
Serial Baud Rate115200
Data Bits / Stop Bits / Parity8 / 1 / NONE
Packet Interval UARTTLn.tm5 ms
Packet Length UARTTLn.len1024
Socket EnableOnly serial port 1, Socket A enabled by default
Offline Cache CACHEnON
Registration Packet REGMDnOFF
Heartbeat Mode HEARTMDnOFF
Heartbeat Interval HEARTTMn60 s
Extended AT EXATALL, NAT@
Reboot on No Downlink Data SOCKRTO1440 min
Remote Device Management RDMOFF

3. Serial Modes and Packetization ​

3.1 Serial Working Modes ​

  • Transparent Mode, default: Serial data is forwarded to the network
  • AT Mode: Serial input is executed as AT commands and network downlink data is discarded

3.2 Entering AT Mode ​

Recommended sequence:

  1. Send +++
  2. Wait, 500 ms recommended and less than 3 s
  3. Send a
  4. Enter AT mode after receiving +ok

Notes:

  • After receiving +++, the device pauses network data output for up to about 3 s
  • AT mode is not saved across power cycles; the device returns to transparent mode after reboot

Exit AT mode with AT+EXIT or reboot the device.

3.3 Packetization, AT+UARTTLn ​

Transmission is triggered when either condition is met:

  • Length trigger: len >= packet length, range 64 to 1024
  • Interval trigger: inter-character gap >= packet interval, range 1 to 300 ms

Example:

text
AT+UARTTL1=30,1024
AT+REBOOT

4. Data Transfer and Sockets ​

4.1 Protocol Types ​

In the vendor AT command set, SOCKns.type supports:

  • TCPC: TCP client
  • UDPC: UDP client
  • HTPC: HTTP client, only on SOCKnA
  • EDP: Peer-to-peer transmission, only on SOCKnA
  • SMS: SMS transparent transmission, only on SOCKnA
  • MQTT: MQTT, only on SOCKnA
  • HYTCP / HYMB: Cloud service forwarding, only on SOCKnA

4.2 Typical Configuration Flow, TCP Example ​

text
AT+SOCKEN1A=ON
AT+SOCK1A=TCPC,test.huayuniot.com,8168
AT+REBOOT

4.3 HTTP Example, POST ​

text
AT+SOCK1A=HTPC,www.rt-thread.com,80
AT+HTPURL1=/service/echo
AT+HTPHD1=Connection:keep-alive
AT+HTPREQ1=POST
AT+REBOOT

5. AT Command Conventions ​

5.1 Format Rules ​

  • Commands start with AT+ and end with \r or \n
  • Commands are case-insensitive, uppercase is recommended
  • Maximum command length is 256 bytes
  • Multiple parameters are separated by commas
  • Wait for the previous command response before sending the next one, maximum timeout about 12 s
  • In command names, n represents the serial port number such as 1 or 2, and s represents the Socket channel A/B

Call forms:

  • Query: AT+CMD or AT+CMD?
  • Set: AT+CMD=v1,v2,...
  • Help: AT+CMD=?

5.2 Error Codes ​

Error CodeMeaning
ARGSInvalid parameter
ARGCWrong number of parameters
CMD_UNKNOWNUnknown command
CMD_FORMATInvalid format
CMD_LENGTHCommand too long
DEV_MEMORYMemory error
DEV_SAVESave failed

6. AT Command Quick Reference ​

6.1 Basic Control and Status ​

CommandFunctionNotes
AT+LISTCommand listPreferred for debugging
AT+EXITExit AT modeReturns to transparent mode
AT+REBOOTReboot deviceApplies parameters
AT+RSTCFGRestore backup parametersEquivalent to Reload
AT+BKCFGBack up current parametersRecommended after configuration
AT+CLRCFGRestore factory parametersFull factory reset
AT+DEVINFODevice informationMODULE / VERSION / IMEI / SN and more
AT+SOCKLKQuery TCP client statusReturns OFF for UDP or TCP server
AT+CSQSignal strength0 / 1 / 2 to 30 / 31 / 99
AT+CEREGNetwork registration status0 not registered, 1 registered
AT+CGATTData network attach status0 detached, 1 attached
AT+IPQuery IPv4 addressCurrent network address
AT+IMEIQuery IMEI15 digits
AT+ICCIDQuery ICCIDUsually 20 digits
AT+IMSIQuery IMSIUsually 15 digits
AT+PING=addrPingReturns latency or error reason

6.2 Serial, APN, and Socket ​

CommandRange / Default
AT+UARTn=<baud>,<data>,<stop>,<parity>,<fc>baud 2400 to 460800, default 115200; data 7/8; stop 1/2; parity NONE/EVEN/ODD; fc NFC/485, default 485
AT+UARTTLn=<tm>,<len>tm 1 to 300 ms, default 5; len 64 to 1024, default 1024
AT+CACHEn=<state>ON, default / OFF
AT+APN=<state>,<apn>,<user>,<pass>,<auth>state: 0 default APN, default / 1 custom; auth: 0 NONE / 1 PAP / 2 CHAP
AT+SOCKENns=<state>ON / OFF, only 1A enabled by default
AT+SOCKns=<type>,<addr>,<port>type see Section 4; addr up to 64 bytes; port depends on protocol

6.3 HTTP and MQTT ​

CommandRange / Default
AT+HTPURLn=<url>URL 1 to 64 bytes, valid for POST
AT+HTPHDn=<hd>Header 1 to 64 bytes, use `
AT+HTPFTn=<state>ON, default and filters HTTP header / OFF
AT+HTPREQn=<request>GET / POST / AUTO
AT+HTPTOn=<to>1 to 30 s, default 6
AT+MQCONFn=<ver>,<clean>,<keepalive>ver 3/4, default 4; clean 0/1, default 1; keepalive 30 to 65535 s
AT+MQAUTHn=<id>,<user>,<pass>ID 1 to 64; user 1 to 64; pass 1 to 128
AT+MQSUBn=<enable>,<topic>,<qos>enable 1, default / 0; topic 1 to 64; qos 0/1/2
AT+MQPUBn=<enable>,<topic>,<qos>,<retain>Publish enabled by default; qos default 0; retain default 0
AT+MQWILLn=<enable>,<topic>,<qos>,<msg>,<retain>Last will configuration
AT+MQMDn=<mode>STD, default / ALI

6.4 SMS, Registration Packet, Heartbeat, and Transparent AT ​

CommandRange / Default
AT+SMSS=<num>,<msg>Send SMS; msg does not support CR or LF
AT+REGTPn=<type>IMEI / ICCID / USER
AT+REGMDn=<mode>OFF, default / FIRST / EVERY / ALL
AT+REGDATn=<data>,<fmt>fmt: HEX, up to 64 bytes / ASCII, up to 32 bytes
AT+HEARTMDn=<mode>OFF, default / UART / NET
AT+HEARTTMn=<time>1 to 86400 s, default 60
AT+HEARTDATn=<data>,<fmt>fmt: HEX / ASCII
AT+EXAT=<mode>,<key>mode: OFF / NET / UART / ALL, default ALL; default key NAT@
AT+SOCKRTO=<time>0 to 4320 min, default 1440; 0 disables the function
AT+DOWNLOAD=<uri>HTTP download upgrade, returns OK or +ERROR:FAIL
AT+DTCVTn=<up>,<down>Data conversion: RAW / BTS / STB; up is serial-to-network and down is network-to-serial

7. Modbus Polling and JSON Reporting ​

The vendor AT documentation provides a full command family:

  • AT+MODBUSn: Modbus TCP / RTU gateway enable
  • AT+MBCFGn: Polling enable, interval, and period
  • AT+MBCMDn: Polling command, HEX format, multiple commands separated with |
  • AT+MBJSn: Combined Modbus and serial transparent reporting mode
  • AT+HJREG: Register point table configuration for JSON
  • AT+JSERRn: Control whether failed reads are reported as null
  • AT+JSUDn, AT+JSTMn, AT+JSIMEIn, AT+JSICCIDn, AT+JSIOn, AT+JSGPSn: Additional JSON fields

Key ranges from the vendor documentation:

  • MBCFGn.tv: 100 to 35535 ms
  • MBCFGn.period: 1 to 2592000 s
  • MBJSn.mode: OFF / POLL / ALL

8. Maintenance, Upgrade, and Exception Handling ​

8.1 Upgrade ​

  • Local USB upgrade, driver required
  • HTTP upgrade through AT+DOWNLOAD=host:port/path.bin

8.2 Parameter Partitions ​

  • Parameter Area: Current runtime parameters
  • Backup Area: Saved with AT+BKCFG, restored with AT+RSTCFG
  • Factory Area: Restored with AT+CLRCFG

Recommended flow:

  1. Configure parameters.
  2. Run AT+BKCFG.
  3. Use AT+RSTCFG when rollback is required.

8.3 Exception Self-Recovery ​

  • AT+SOCKRTO=<time> controls automatic reboot on no downlink data
  • Default value is 24 hours, suitable for unattended deployments

9. Troubleshooting ​

SymptomCheck Steps
Cannot register to the networkCheck AT+CSQ, AT+CEREG, AT+CGATT, SIM status, and antenna status
Network is up but server is not connectedCheck SOCKEN and SOCK parameters and use AT+SOCKLK to view connection status
Serial data is abnormalVerify AT+UARTn settings match the field device and check UARTTLn packetization parameters
HTTP or MQTT failsCheck HTP* or MQ* parameters one by one and verify basic TCP transparent transmission first
Registration packet or heartbeat is invalidCheck whether REG* or HEART* is enabled and whether the mode matches the application
Frequent rebootCheck whether AT+SOCKRTO is set too short
Remote transparent AT does not workCheck AT+EXAT mode and key, default ALL,NAT@
  • Manufacturer: Hunan YenGear Tech Co., Ltd.
  • Address: Room 21014, Building 1, Fudi Xingguang Tiandi, Yingxin Road, Yuhua District, Changsha, Hunan, China
  • Email: hi@yengear.com
  • Website: www.yengear.com