Hi, I'm doing " Send SMS from your Arduino by phone" based on: http://murchlabs.com/send-sms-from-your-arduino/ But I have a problem a bout headset plus: - My motorola only use 4 pole headset plug and I don't know how to wire this headset plug and my arduino: 3 pole pinout: 4 pole pinout: Tx corresponds with??? Rx corresponds with???
If your Motorola phone has a 4-pole headphone jack, the odds of it being compatible is very small.
You don't mention what model of phone you have - have you even thought of it being incompatible?