Hackers have multiple avenues for accessing Industrial Control System (ICS) and can adversely impact network hardware, operating systems, and executables. This includes attacking hardware/software switches commonly used in waste water, water treatment, and power substation facilities. Unauthorized network intrusion can be mitigated by augmenting Media Access Control (MAC) based device identity (ID) verification processes using Physical-Layer (PHY) features. PHY augmentation is addressed here using Constellation Based Distinct Native Attribute (CB-DNA) features derived from unintentional Ethernet cable emissions. Collected emission symbols are mapped to a gradient-based binary constellation space where, for the first time, conditional constellation symbol features are used for device ID verification. Serial number discrimination is assessed using 16 devices from 4 different manufactures, with 12 serving as authorized devices and 4 (one from each manufacturer) serving as attacking rogue devices. Collectively considering 12,288 rogue attack scenarios using 256 verification models, the proposed CB-DNA method is promising and yielded average Rogue Reject Rates (RRR) of 85.2%