Good news, everyone!
The D-Star link to ERDN is active and under my testing, has performed very well so far. I ask you that if you have a chance, please do try to use it.
XLX740 C - ERDN D-Star Link
Connect to XLX740 C by changing your radio's URCALL to XLX740CL and momentarily pressing the PTT button. You should hear a "Linked to XLX740 Charlie" or something similar. Then, switch URCALL back to CQCQCQ, and talk normally. Other users on ERDN should be able to hear you.
If using XLX740CL does not work, you may also try XRF740CL, since a lot of repeaters are subscribed to the XRF reflector list.
If you find a repeater that does not have a connection to XLX740, do get in contact with the repeater's owner and ask them to add in the address to XLX740 into their host file.
IP Address: 220.127.116.11
*** ERDN is a network of many links into a central hub. When transmitting, please hold your PTT button for a couple seconds before speaking to allow all linked systems to start receiving your audio. Also, please allow 4-5 seconds between each transmission to allow remote repeaters and links to reset timeout timers that may be enabled. ***