Today i had no land line so i got a MJ for the sole purpose to use with a credit card machine I got only 3 of like 20 trys to go threw aqnt ony using a mj to process credit cards
The setup would be similar to a fax machine. Try setting your CC machine to the lowest baud rate available and make sure that error correction is turned off. Use an XP machine, I've never had any luck with Vista and faxing with mJ.