# USB Mode on GSM SIM800C – Quad-band, GPRS, Bluetooth

> SIM800C quad-band GSM module with USB connection via CH340T converter, appears as a virtual serial port on PC. Supports SMS, voice calls and GPRS data (multi-slot, max 85.6 kbps) through AT commands, plus Bluetooth 2.4 GHz IEEE802.15. Powered by 5 V DC via USB, auto-elastic Micro/Nano SIM slot, SMA antenna connector, LED network status indicator. Compatible with Arduino, STM32, ESP32.

- Page: https://sigmanortec.ro/en/usb-mode-on-gsm-sim800c-quad-band-gprs-bluetooth
- Price: 67.74 RON
- Availability: In stock; 1-2 zile
- Reference: 88206 · EAN: 5945795457187
- Category: Mechatronics and IoT > Sensors and Modules > GSM
- Specifications: Input Voltage: 5 V; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.; Microcontroller: SIM800C; Communication interface: GPRS; Frequency bands: Quad-band; Connectivity: Bluetooth
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 04:49 (Europe/Bucharest)

## Description

Compact solution for GSM connectivity in automation and prototyping projects, it allows SMS, voice calls, and GPRS data transfer via AT commands. It connects directly to a PC via 5V USB thanks to the CH340T and appears as a virtual serial port. It works globally on quad band 850 900 1800 1900 MHz, includes Bluetooth and an SMA connector for the antenna, compatible with Arduino, STM32 and ESP32.
This USB to GSM module integrates the SIM800C chip from SIMCom and the CH340T USB-serial converter, allowing direct connection to a computer via the USB port. It supports Quad-band 850/900/1800/1900 MHz frequencies, operating on GSM/GPRS networks globally. It is suitable for sending and receiving SMS, voice calls, data transmission via GPRS (2G), and Bluetooth communications (2.4 GHz, IEEE802.15 standard). The board is powered automatically when connected via USB, powers on by itself, and connects to the network. It includes a SIM card slot (Micro SIM or Nano SIM), GSM and Bluetooth antennas, and a LED indicator for network status, which blinks rapidly every 1 second when there is no network or the SIM card is not detected. The LED blinks once every 3 seconds when the module is connected to the network.
The module supports data transmission via GPRS and Bluetooth.
Specifications:
Chipset: SIM800C
USB-serial converter: CH340T
GSM Bands: Quad-band 850/900/1800/1900 MHz
GPRS: Multi-slot, maximum speed 85.6 kbps
Bluetooth: 2.4 GHz, IEEE802.15 standard
Power supply voltage: 5 VDC via USB
PC interface: USB (virtual COM)
SIM slot: Auto-elastic, compatible with Micro SIM / Nano SIM
Antenna connectors: SMA
LED indicator: Power and network status (fast = no network / SIM, slow = connected)
Supported commands: AT (baud rate adjusts automatically)
Layout:
Usage:
Setup - Insert an active SIM card (Micro or Nano) into the auto-elastic slot. Connect the GSM antenna to the marked connector.
Connection to PC - Connect the module to an available USB port. It will be recognized as a virtual serial port (COMx on Windows, /dev/ttyUSBx on Linux). Install the CH340T driver if not already present.
Testing - Open a serial terminal (for example, Arduino IDE Serial Monitor). Send the AT command. The module should respond with OK.
Essential AT commands:
AT+CSQ - signal quality
AT+CREG? - registration status (1 or 5 = connected)
AT+CMGF=1 - set SMS text mode
AT+CMGS="+40xxxxxx" - send SMS (then write the message and finish with Ctrl+Z)
Dimension diagram:
Package contents:
1 x USB to GSM SIM800C Module
1 x GSM Antenna