Y201-G Technical Manual

Y201-G Specification

Contents

1. Overview
   • Hardware Wiring
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 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.

Item	Description
Uplink	4G Cat.1
Serial Interface	One serial port with RS232, RS485 or TTL interface options
Socket Channels	Multiple network channels on the single serial port, Socket A enabled by default
Maintenance Methods	Config tool, serial AT, network AT, SMS AT

1.1 Hardware Wiring

Power off before wiring. Select the ordered serial interface and use the terminal labels on the supplied module. The drawings show electrical connections, not connector pin order.

Module power: 9-36 VDC. Connect supply positive to + and negative to -.

RS485 variant: A to A, B to B, signal GND to GND. TX/A and RX/B are the shared terminal labels. Use a twisted pair and terminate only the two physical bus ends when required.

RS232 / TTL variant: cross TX and RX; connect GND to GND. Match the adapter's electrical interface and verify the TTL logic voltage before connecting.

See the Y201 User Manual for model-specific power and uplink connections.

2. Default Parameters

Parameter	Default
Serial Baud Rate	9600
Data Bits / Stop Bits / Parity	8 / 1 / NONE
Packet Interval UARTTLn.tm	5 ms
Packet Length UARTTLn.len	1024
Socket Enable	Only Socket A on the single serial port enabled by default
Offline Cache CACHEn	ON
Registration Packet REGMDn	OFF
Heartbeat Mode HEARTMDn	OFF
Heartbeat Interval HEARTTMn	60 s
Extended AT EXAT	ALL, NAT@
Reboot on No Downlink Data SOCKRTO	1440 min
Remote Device Management RDM	OFF

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:

AT+UARTTL1=30,1024
AT+REBOOT

4. Data Transfer and Sockets

4.1 Protocol Types

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

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

4.3 HTTP Example, POST

AT+SOCK1A=HTPC,www.example.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 is 1, identifying the single physical serial port, 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 Code	Meaning
ARGS	Invalid parameter
ARGC	Wrong number of parameters
CMD_UNKNOWN	Unknown command
CMD_FORMAT	Invalid format
CMD_LENGTH	Command too long
DEV_MEMORY	Memory error
DEV_SAVE	Save failed

6. AT Command Quick Reference

6.1 Basic Control and Status

Command	Function	Notes
AT+LIST	Command list	Preferred for debugging
AT+EXIT	Exit AT mode	Returns to transparent mode
AT+REBOOT	Reboot device	Applies parameters
AT+RSTCFG	Restore backup parameters	Equivalent to Reload
AT+BKCFG	Back up current parameters	Recommended after configuration
AT+CLRCFG	Restore factory parameters	Full factory reset
AT+DEVINFO	Device information	MODULE / VERSION / IMEI / SN and more
AT+SOCKLK	Query TCP client status	Returns OFF for UDP or TCP server
AT+CSQ	Signal strength	0 / 1 / 2 to 30 / 31 / 99
AT+CEREG	Network registration status	0 not registered, 1 registered
AT+CGATT	Data network attach status	0 detached, 1 attached
AT+IP	Query IPv4 address	Current network address
AT+IMEI	Query IMEI	15 digits
AT+ICCID	Query ICCID	Usually 20 digits
AT+IMSI	Query IMSI	Usually 15 digits
AT+PING=addr	Ping	Returns latency or error reason

6.2 Serial, APN, and Socket

Command	Range / Default
AT+UARTn=<baud>,<data>,<stop>,<parity>,<fc>	baud 2400 to 460800, default 9600; 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

Command	Range / Default
AT+HTPURLn=<url>	URL 1 to 64 bytes, valid for POST
AT+HTPHDn=<hd>	Header 1 to 64 bytes, use | for multiple headers
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

Command	Range / 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 full Modbus 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:

• 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

Symptom	Check Steps
Cannot register to the network	Check AT+CSQ, AT+CEREG, AT+CGATT, SIM status, and antenna status
Network is up but server is not connected	Check SOCKEN and SOCK parameters and use AT+SOCKLK to view connection status
Serial data is abnormal	Verify AT+UARTn settings match the field device and check UARTTLn packetization parameters
HTTP or MQTT fails	Check HTP* or MQ* parameters one by one and verify basic TCP transparent transmission first
Registration packet or heartbeat is invalid	Check whether REG* or HEART* is enabled and whether the mode matches the application
Frequent reboot	Check whether AT+SOCKRTO is set too short
Remote transparent AT does not work	Check AT+EXAT mode and key, default ALL,NAT@

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• 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