mkr1000 and SIM800L

Hardware MKR Family MKR1000
1

Hello to everybody,
i have buy a gsm module

http://www.ebay.it/itm/Smallest-SIM800L-GPRS-GSM-Module-Card-Board-Quad-Band-Onboard-With-Antenna-/122308552183?hash=item1c7a2865f7:g:OHgAAOSwnHZYdzzw

and try to study how connect this module to the mkr1000, but i'm not sure (and if) is necessary protect TX and RX pin

GSM -> mkr1000

VCC -> diode 1N4007 -> 5V
RXD -> (directly or with resistor?) pin 14
TXD -> (directly or with resistor?) pin 13
GND -> GND

Thanks in advace for the help.