Gary Stephens replies
Yes, you can use a modem on the remote support port set to auto answer. This will definitely work. It was more about controlling access to the console remotely. I recall one site that had a modem with a remote call-back to a known inbound number that was effective. Upon answer you were prompted for a U and P that had a dial-back associated with it. Ultimately it's all down to risk and your appetite for change.
Billy Brewer adds
You could hook up a cheap laptop connected to the console port (with a USB to serial converter). Then use TeamViewer or any shared desktop utility you prefer.
Tracy Johnson reports
An older PC with one NIC (you can remote into) and a serial port will also do. These days we just have a PC as the console via a terminal emulator (Minisoft, Reflection, or QCTerm). We use two NICs and just remote into the PC and open a window from there to do our remote reboots.
Mark Ranft notes
All the newer A- and N-Class systems have IP configurable remote console. I assume yours is an older system.
The PC options are excellent. If you have a DTC, you can set up back-to-back DTC switching. You configure a host (outbound) port on the DTC and you choose it by IP and TCP port ID.