# LILYGO T-Call SIM800

> ESP32 board with SIM800L 2G GSM/GPRS modem for SMS alerts, voice calls, and cellular data — ideal for remote monitoring and IoT projects needing cellular fallback on a budget.

## Quick Facts

- **Brand:** LILYGO
- **Board Type:** dev-board
- **Price:** ~$16.51
- **Product Readiness:** developer
- **CPU:** Xtensa LX6 dual-core @ 240MHz, FPU, HW crypto (AES/SHA/RSA)
- **CPU Architecture:** Xtensa LX6
- **CPU Cores:** 2
- **RAM:** 520KB SRAM
- **PSRAM:** 8MB QSPI
- **Flash:** 4MB
- **USB:** USB-C 2.0
- **Power:** 5V + LiPo
- **Operating Voltage:** 3.3V
- **Battery:** LiPo (user-supplied, 1.25mm JST)
- **Charging Port:** USB-C
- **Antenna:** Built-in PCB antenna

## Connectivity

- **Wifi:** 802.11 b/g/n
- **Bluetooth:** BLE 4.2
- **Cellular:** GSM/GPRS 2G (SIM800L)

## Open Source

- **Firmware:** Yes
- **Schematics:** No
- **PCB Layout:** No

## Compatible Firmware

arduino, micropython, esphome, platformio

## Use Cases

- cellular-iot
- environmental-monitoring
- asset-tracking
- iot

## Components

- **ESP32-D0WDQ6** (mcu): Espressif ESP32-D0WDQ6 dual-core Xtensa LX6 at 240MHz with WiFi and Bluetooth 4.2/BLE. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.espressif.com%2Fsites%2Fdefault%2Ffiles%2Fdocumentation%2Fesp32_datasheet_en.pdf&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)
- **SIM800L** (cellular-modem): SIMCom SIM800L quad-band GSM/GPRS modem supporting SMS, voice calls, and GPRS data up to 85.6 kbps. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fsimcom.ee%2Fdocuments%2FSIM800L%2FSIM800L%2520Hardware%2520Design_V1.00.pdf&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)
- **IP5306** (battery-charger): INJOINIC IP5306 2A LiPo charger and boost converter with battery level indication. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fdatasheet.lcsc.com%2Flcsc%2F2110231230_INJOINIC-IP5306_C181749.pdf&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)
- **CH9102** (usb-uart): WCH CH9102 USB-to-UART converter for programming and serial debug. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.wch-ic.com%2Fdownloads%2FCH9102DS1_PDF.html&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)

## Protocols

- **UART**: TX: GPIO1, RX: GPIO3
- **I2C**: SDA: GPIO21, SCL: GPIO22
- **SPI**: MOSI: GPIO23, MISO: GPIO19, CLK: GPIO18

## GPIO Map

| Pin | Name | Type | Functions |
|-----|------|------|-----------|
| GPIO0 | Boot / Free GPIO | GPIO | digital-input, strapping |
| GPIO4 | SIM800 PWRKEY | GPIO | digital-output |
| GPIO5 | SIM800 RESET | GPIO | digital-output |
| GPIO26 | SIM800 RX | UART | digital-input |
| GPIO27 | SIM800 TX | UART | digital-output |
| GPIO21 | I2C SDA | I2C | digital-input, digital-output |
| GPIO22 | I2C SCL | I2C | digital-output |
| GPIO34 | Free ADC Input | ADC | digital-input, adc, input-only |
| GPIO35 | Free ADC Input | ADC | digital-input, adc, input-only |

## Description

## Overview

The LILYGO T-Call combines the Espressif ESP32 dual-core processor with a SIMCom SIM800L quad-band 2G GSM/GPRS modem, enabling SMS messaging, voice calls, and GPRS data communication in a compact development board. While 2G networks are legacy in some regions, the SIM800L remains widely useful for IoT applications that require low-data remote connectivity, SMS alerts, or operation in areas where only 2G coverage exists.

The board provides 4MB or 8MB flash options, 8MB PSRAM, WiFi 802.11 b/g/n, and Bluetooth 4.2 via the ESP32, allowing it to bridge cellular data to local wireless networks. The IP5306 power management IC handles LiPo battery charging and output, making the board suitable for battery-backed standalone deployments with a user-supplied LiPo cell.

A USB-C port with CH9102 serial bridge enables programming, while standard 0.1-inch headers expose I2C, SPI, UART, I2S, and CAN interfaces. The T-Call is popular for DIY GPS trackers, automated SMS alert systems, and agricultural monitoring nodes where cellular data is preferred over WiFi.

## Where to Buy

- [LILYGO Official](https://openhardware.directory/r?to=https%3A%2F%2Flilygo.cc%2Fproducts%2Ft-call-v1-4&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export) — $16.51

## Resources

- [product](https://openhardware.directory/r?to=https%3A%2F%2Flilygo.cc%2Fproducts%2Ft-call-v1-4&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)
- [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2FXinyuan-LilyGO%2FLilyGo-T-Call-SIM800&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)
- [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fwiki.lilygo.cc&ref=openhardware.directory&product=lilygo-t-call-sim800&source=md-export)

## Tags

`esp32`, `sim800l`, `gsm`, `gprs`, `2g`, `cellular`, `lilygo`, `sms`, `iot`

## Images

![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/2ff914e08d17.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/5a8ee76e9d1d.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/cbabba026744.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/ba549a70d683.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/589cfd1b5f32.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/4be052a73b4f.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/c350b5df23d4.jpg)
![LILYGO T-Call SIM800](https://nbg1.your-objectstorage.com/openhardware-directory/entities/lilygo-t-call-sim800/67379abaa904.jpg)

> **Battery Powered:** Li-Po

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