HI guys; i bought a gsm modem, but there's more than one tx and rx pins(unlike the previous one i bought), the pins are not labeled; i have problem in determining which tx and rx to use; here is a link for its specifications :
http://www.ebay.com/itm/Arduino-GSM-SIEMENS-TC35-Module-Board-RS232-UART-Serial-Voice-adapter-/281126880318?pt=LH_DefaultDomain_0&hash=item417477c43e
if any one can help me i would be grateful...
This download might help:
http://www.sainsonic.com/zen/albums/Resource/20/20-012-101/TC35I%20cd.rar
It includes TC35I.pdf: TC35i Hardware Interface Description
RXD_MCU_TTL
TXD_MCU_TTL
Will do?
Cause MCU is Microcontroller Unit. I thought. 