[HECnet] Disallow login on DZ line in VMS

The recent thread "Disallow system from dz lines (OpenVMS/VAX 7.3)" = started me wondering how to entirely disable the login prompts on a = given serial line, such as to use the port for some other purpose like = controlling external hardware. I've been trying to find out how to do = that in the manuals, but I haven't found it yet. It seems like it might = be something to do with SET TERM, but I don't see obvious flags for = that. Can anybody offer any hints? I won't be too surprised if my eyes = have already glided over the answer in the manuals and HELP SET TERM = text.