Development Board Module Kit Fit for 850/900/1800/1900 MHz GPRS/GSM Antenna, 5~26V
- Computer debugging USB--TTL. This module is powered by: 5V-26V, 5V 2A power supply is recommended. After plugging in the motherboard, the power supply must be able to supply 2A. The reason is that the GPRS Shield startup current and the maximum top current required to work up to 2A, but the USB port can not provide such a large current, so the external power supply equipment must be provided..
- The other power supply port leads to the 3.7--4.5V power supply for lithium battery power supply. The serial port is perfectly compatible. The TTL serial port is compatible with 3.3 and 5V microcontrollers..
- Make sure your SIM card is not locked. The best baud rate for GPRS Shield communication is 19200 BPS 8-n-1 (GPRS Shield automatically matches baud rate by default). Quad-Band 850 / 900/ 1800 / 1900 MHz - would work on GSM networks in all countries across the world..