pylon:
If you prepare the data you send out you can use the standard implementation of SoftwareSerial (or HardwareSerial) to send and receive it. 7E1 is 8N1 with the MSB set to the result of xoring the other seven bits. What speed do you use for the communication with the smartmeter?
It requires sending the string /?! before it will pass back its data. My infrared adapter will blink when Arduino is sending (checked via camera), but the Smartmeter doesn't answer.
It requires 300 boud.
A german page about the topic: hardware:channels:meters:power:edl-ehz:elster_as1440 [wiki.volkszaehler.org]
René