The amount of gear going into our datacenter that has a serial console management interface was starting to increase and the number of miscellaneous serial cables going into our servers to manage them was starting to get out of hand (even the datacenter people had started to notice the cable mess - not a good look as datacenter staff can be notoriously picky when it comes to cable tidiness). Plus we'd put some switches into our DMZ to handle gear going into a 'blue' (infrastructure internet gear) and 'red' (public facing services) zone as legs off our firewall appliance. So being able to tweak and check settings on these switches and the firewall appliance itself (should the management web interface be unavailable) was pretty important.
So I went looking for options and discovered the Sena PS 810 - its not a full on 'Console Server' but it does just enough to be useful in terms of providing a telnet console to a serial interface. Sena do make the VTS series which is pitched as a Console Server with more features but from what I can gather its quite a bit more expensive - unless you need all the extras you might find the PS series sufficient for you needs.
Serial and console servers are available from a number of vendors - they used to be more common but as the serial port becomes less important they've become a little more obscure and harder to find. I've heard the HP ones are pretty good and I'm sure the other major vendors have them available too.
What the Sena PS 810 lets you do -
- Manage and setup the Sena via web interface
- Map serial ports to telnet ports (ie map serial port 1 to 8 to a telnet port number) - telnet to the Sena on the port number and you'll connect to the serial device
- Convert serial to IP connections and do com port redirection - ie if you have a bunch of serial devices in a factory you can plug them into this device and remotely control/monitor them as if they were local com ports on a remote computer - we don't need that capability but it could be useful if you need to monitor several UPS devices for example.
What it doesn't let you do -
- Control the serial device via a web interface (a full blown 'Console Server' will usually let you do this)
I have a feeling it also does support the ssh to serial mapping but I haven't had a chance to experiment with this. We've put this device on our back-end non-routed management network so there is an element of security provided.