Problem solved!
I adjusted the udp.cfg to:
# Port to listen for incoming connections
port=25001
# Allow masks in ip:port addressing, e.g. 192.168.0.1:* etc
addressmask=true
# Used character set
charset=ASCII
It’s the “addressmask” that needed to be changed.
I also changed my item to:
String Tex_UDP_Incoming1 "Incoming UDP String1 [%s]" <settings> (gSet) { udp="<[192.168.3.10:*:'REGEX((.*))']" }
My item is now populated with the ASCII information from the UDP package.
Thanks Udo for helping me out on this!