I haven't ranked either #2 or #3 but I liked the idea of turning HAL into an emblem. I preferred #2 over #3 but I don't think there is an L shown in #2. HAL is much easier to remember than Hytsio Aboa Ltd. It makes the complex (full name) simple (acronym), which is what I try to do for customers when explaining how IT systems work together.
Do you have any other ideas?
To inspire you further, I deal with the whole range of IT communications networks, from global (satellites and cables) to local (4G and radios) as well as all the Infrastructure that send traffic over them (mobile devices, desktops to data centres) from Land, Sea and Air.