The GPL source code contained in Comtrend product is available for free download in here.

Product Code
VR-3031u RA31-412CTL-C01_R01
NL-3110u IA11-412CTU-C01_R02
CT-5372 G111-310CTL-C05_R02
VG-8040un I601-S406CTL-C01_R01
VI-3223u M631-S406CTL-C01_R02
AI-5720u N011-S406CTL-C01_R01
CT-5611 B011-306CTG-T01_R01
NexusLink3100u N611-406CTU-C02_R01
NexusLink5600u K611-406CTU-C03_R02
VR-3026e H641-406TO2-C01_R06
CT-5621/CT-5621T
CT-5361/CT-5361T		 A131-306CTU-C04_R01
NexusLink5631 H131-310CTU-C05_R01
NexusLink5631E H111-310CTL-C02_R10
AR-5382u A731-406CTL-C01_R04
AR-5382eu A741-406CTL-C01_R03
CT-5072T(AR-5062) B031-404CTU-C02_R01
CT-5364A A431-312CTU-C02_R06
CT-5363 C131-310CTU-C08_R01
CT-5374 O411-402CTL-T03_R04
VR-3022u H631-406CTL-C01_R03
GI-4250un R751-S410FCV-C01_R02