SysAdmin Sunday: The Briel PockeTerm

It happens, sometimes: your system has a critical failure and you need to access it via a serial port for a true hardware console. Maybe the video card died, maybe there is not a video card. Maybe your system uses LOM and you need to access it. In these and many other cases it is very handy and necessary to have a serial terminal available. For decades most laptops came with regular DE-9 serial ports but now very few still have them. In the effort to remove "legacy" ports and also to slim machines nearly all have gone to only having a couple or more USB ports and relying on adapters to gain access to these older connections. Occasionally, though, running a port over USB causes some compatibility issues.

In cases such as this it might be advisable to use a serial terminal converter. In a large installation with a high grade KVM setup it may be worth while to purchase something like the Raritan AUATC (ASCII Terminal Converter). This will integrate into a large KVM infrastructure and allow an admin to access the serial console via their normal KVM infrastructure. The AUATC is an expensive piece of hardware much of the time. This is fine for critical uses where the ability to administer the machine makes that cost palpable, but this could add almost a third to the cost of many servers just to dedicate an AUATC to it.

Enter the Briel PockeTerm. While this does not offer the finished product like Raritan, nor the KVM integration, it is much less expensive and an open project so that it can be configured as needed to support nearly any serial function. The project is based on the Parallax Propeller platform, also seen on the DefCon 16 badge. The PockeTerm is available in a few flavors, from fully built boards down to bare PCBs, and Vince Briel has published fairly extensive documentation on the device, including schematics, and firmware code. While this is not a turn key device it is significantly less expensive and open to being modified for application specific uses.

This also makes it useful for it's original target- vintage computers. The PockeTerm can be put into a small project enclosure and be paired with a common consumer grade KVM or used with a spare VGA capable monitor and keyboard. Adding the PockeTerm to a small VGA LCD screen and a compact keyboard would create a very portable standalone terminal for use in a data center crash cart and or a other uses where a serial console would be desirable on the go. The PockeTerm would also be very easy to stash in a rack drawer to be ready for use on uncommon situations where having a dedicated terminal converter would be prohibitive.

There are other solutions of this type available, but this one comes from a well known source and has yet to be fully commercialized. Often first run projects are sold at or just above cost to cover the initial setup costs and are more expensive than other projects that have been fonalized and can take advantage of economies of scale.

Hack-A-Day article on the PockeTerm

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