TTGO T-Call ESP32 with SIM800L GPRS Module

Hardware Specifications:

• Chipset: ESPRESSIF-ESP32 240MHz Xtensa® single-/dual-core 32-bit LX6 microprocessor
• FLASH Memory: QSPI flash 4MB / PSRAM  8MB
• SRAM: 520 KB SRAM
• Button: Reset
• USB to TTL IC: CP2104
• Modular interface: UAR, SPI, SDIO, I2C, LED PWM, TV PWM, I2S, IRGPIO, capacitor touch sensor, ADC, DACLNA  pre-amplifier
• On-board clock: 40MHz crystal oscillator 
• Working voltage: 2.7V-3.6V
• Working current: About 70mA
• Sleep current: About 300uA
• SIM card: Only supports Nano SIM card
• Working temperature range: -40℃ ~ +85℃
• Size&Weight: 78.83mm*28.92mm*8.06mm(11.77g)

Power Supply Specifications:

• Power Supply: USB 5V/1A
• Charging current: 500mA
• Battery: 3.7V lithium battery (Not included)
• JST Connector: 2Pin 1.25mm
• USB: Type-C

Wi-Fi:

• Standard: FCC/CE-RED/IC/TELEC/KCC/SRRC/NCC
• Protocol: 802.11 b/g/n(802.11n, speed up to150Mbps)A-MPDU and A-MSDU polymerization, support 0.4μS Protection interval
• Frequency range: 2.4GHz~2.5GHz(2400M~2483.5M)
• Transmit Power: 22dBm
• Communication distance: 300m

GSM/GPRS SIM800L:

• Quad-band 850/900/1800/1900MHz
• Connect onto any global GSM network with any 2G SIM
• Send and receive SMS messages.
• Send and receive GPRS data (TCP/IP, HTTP, etc.)
• AT command interface with "auto baud" detection.

Bluetooth:

• Protocol: Bluetooth v4.2BR/EDR and BLE standard
• Radio frequency: -97dBm sensitivity NZIF receiver Class-1,Class-2&Class-3 emitter AFH
• Audio frequency: CVSD&SBC audio frequency

Software Specification:

• Wi-Fi Mode: Station/SoftAP/SoftAP+Station/P2P
• Security mechanism: WPA/WPA2/WPA2-Enterprise/WPS
• Encryption Type: AES/RSA/ECC/SHA
• Firmware upgrade: UART download/OTA (Through network/host to download and write firmware）
• Software Development: Support cloud server development /SDK for user firmware development
• Networking protocol: IPv4, IPv6, SSL, TCP/UDP/HTTP/FTP/MQTT
• User Configuration: AT + Instruction set, cloud server, android/iOSapp
• OS: FreeRTOS