Using a Nokia Card Phone 2.0 he got on Ebay for 10 Euros, a HDC-6D headset (Cost: 1 Euro), a prepaid T-Mobile SIM card (10 euros) and NewtSMS+ 1.10a beta (free), Marcus Hammerschmitt (original post in German and Google-translated) was placing calls with his Newt -- shades of 1997. He explains:
"I installed [NewtSMS+ 1.10a beta] on my Newton MP 2100. I put the SIM card into my Nokia Card Phone. Plugged the card phone into my Newt. Let NewtSMS+ know the PIN of my SIM card, and was ready to go...For my money (exactly 35 euros / about 48 USD in this case), the Newton does a brilliant job."
He goes on to note that the Phone Card also works with his eMate and old Compaq laptop, plus the SIM card works with his Nokia 6310i. Nicely done!