Not aware of any driver issues with RH EL7. Would you be able to provide a typescript of the driver compilation/installation on this host?
# script
# rpmbuild --rebuild 40002086_W.src.rpm
Change to directory /root/rpmbuild/RPMS/(arch):
# cd /root/rpmbuild/RPMS/(arch)
Where (arch) represents your system architecture (for example: i386, x86_64, etc...).
Use rpm to install the new driver package by typing:
# rpm -ivv dgrp-1-9.35(arch).rpm
Configure the Digi Ethernet unit(s) and load the module by typing the following:
# dgrp_cfg_node init (ttyid) (ip_address) (number_of_ports)
The following example configures a 16 port PortServer with device names of ttya00 through ttya15:
# dgrp_cfg_node init a 192.168.1.1 16
Close the typescript:
# exit
Post the file called typescript residing in the directory where the script command was issued for futher analysis.
Digi does support their drivers and will waive any Technical Support fees if there is a bug found and validated.