ICE has all CBP channels in their radios as ICE is the primary investigative agency for all CBP referrals. I'm guessing that is what you probably heard since ICE has an office in Castle Point. They also have all of the various counties 911 channels, NYSP, etc. and I've personally heard them come up on SP CAR-CAR numerous times in the Hudson Valley area.
To differentiate between the two, Alpha units are ICE Special Agents. India units are CBP Officers.
165.2375 NAC $301 simplex is CBP TAC 1. The same frequency in repeater mode is NET 1. They should be in the wiki. There is a NET 1 repeater up on Sam's Point (as well as all over the United States).
Just an FYI...ICE is further broken down into two separate components...Homeland Security Investigations (HSI) and Enforcement and Removal Operations (ERO). ICE/HSI is the primary investigative agency for anything criminal from narcotics smuggling to human trafficking, to child pornography, illegal arms exports, multi-national gangs, etc...basically anything with a nexus to a border which could also be an airport, seaport, or something transmitted through the internet. ICE/ERO handles your administrative types of crimes like the Criminal Alien Program, warrants of deportation, overstays, etc. Two completely different things. HSI is really pushing for a split from the immigration side of things because when people think of ICE all they see is Immigration and not the Customs side.
ICE primarily uses the old INS frequencies but can come up on any of the CBP channels at any time.
