I got a non trivial task - we have 23 servers and we need to have an option to reboot them in case of emergency. of course there are simple solution - follow the ads and buy expensive remote power ip switch modules. 8 Unit block about $500 USD, and them more and more. However we cut our expenses to be 350 + 170 X 4 AUD = PCI GSM Modem + 4 IPSwitch Relays 8 port each. Full control and some engineering.
Here we go
We connected IP Power devices to Servers Motherboard Reset pin. When IP Power output is set to On and then to Off we simulate Reset button and server goes rebooting. this is pretty simple. All this IP Power devices comes with pretty straightforward web interface (of course they?re stand alone microcomputers supplied with network jack and embedded control web browser) that allows to control output relays - so task n1 was solved you may reset all servers through simple web interface.
More interesting goes if you want to make this wireless (imagine your network is down) . We wrote simple SMS Daemon application that periodically polls GSM Modem for incoming SMS messages and parses them, this makes easy implement special commands that will send reboot sequences to IP Power Devices. Of course this is not trivial but it took me one day to build this application on Delphi 5 + Jedi Toolkit. This Application allows almost everything - reboot servers (with IP Power), forward emails, run certain applications, etc and this is all with simple custom built SMS Daemon. It was so good so we decided to release this program very soon as shareware. So stay tuned.
I belive SMS Daemon will be a great help for system administrators and remote data centers support staff.