Originally posted by: j.gann
Even for hmc upgrades the built-in remote access (via vpn if you use a public network) will normally do.
If you are into luxury, look at "kvm over ip"-switches which will not only let you cycle power remotely but also see the boot messages of the underlying linux.
For the rare cases where a hmc upgrade might go wrong, make friends with personnel at the remote site who can press buttons or take screen-shots with a digicam if required.
Anyway, redundant hmc setups are common, where a failed upgrade or other kind of hmc failure will not give you an instant headache.