USB-C PD for an industrial Cisco IR829 router | Hacker News Reader

USB-C PD for an industrial Cisco IR829 router

eloydegen.com

9 pointstranspute14 comments

Much less interesting and DIY, but I discovered cheap USB-C PD to barrel connector cables exist for a variety of different diameters and voltages not so long ago, and they've been great. So convenient to ditch a bunch of wall-warts and plug into a single multi-port GaN charger that can sit on a desk at the end of a normal mains cable.

Just an opinion, but:

Don't buy cables! You already have lots of usb-c cables, probably maybe. Just get a usb-pd to barrel jack adapter. Some are just a little molded plastic with usb-c female on one side (bring your own cable) and the barrel jack on the other. They're ok, have a bunch, but I love the adapters with like ~2 of cable, and that ability to flex & bend rather than sticking out the side is super nice.

It's wild how many huge power bricks I have that are like 24w or 60w that I don't need at all anymore. Usb-c chargers are so small, so cheap, so convenient.

The one caveat about this situation is that the adapters - I think - try to negotiate for a high wattage. Even though my monitor for example tops out at like 24w, the DC barrel jack adapter will greedily ask for 60w or 100w that it won't use. It'd be great to have a fancier version that lets you dial in the amperage asks, so you can let other things use that power on a multi-port charger.

When you talk about an adaptor with 2m of cable, I guess that's really what I'm buying here? There's a USB C plug at one end and a male barrel connector at the other.

Adding another pair of USB C female + USB C male somewhere along the combined cable length would be worse, I think? Especially in the 'dongle' configuration where all that mess hangs right next to one or other end of the cable: hard to hide and the extra bulk makes it easier to unintentionally pull the plug out.

Well, to me, the greatest joy of the usb-c era is not needing a cable for every purpose. A 1m USB4 cable is all I need. Then I can attach either a HDMI adapter to the end, a DisplayPort adapter, a HDMI mini adapter, a HDMI micro adapter, a DisplayPort mini adapter, a USB micro adapter, a USB mini adapter, a USB-b adapter, or a 20v, 15v, 12v, 9v, or 5v DC barrel jack adapter. I no longer need a cable stash for each one of these cables.

Sometimes yeah having dedicated cables is nice, but personally I've been able to find much more joy by adapters, by reusing the same general purpose cables for all sorts of purposes, rather than having specific cables for specific use.

I have rarely found downside to this setup. The extra usb-c female and male don't seem to make any practical impact.

Plus a plethora of right-angle and U-shaped adapters, and cables/connectors which report voltage and current on tiny display.

Over time I've been converting lots of my equipment to USB-C. Having tried various PD sinks, I've settled on CH224K. It works very well (in fact, I'm typing this on an old HP laptop that's powered from USB-C using a CH224K adapter I made). Would recommend.

https://hackaday.io/project/187112-ch224k-usb-pd-decoy

https://github.com/wagiminator/Power-Boards/tree/master/USB-...

https://www.laskakit.cz/user/related_files/ch224ds1.pdf

These USB-C PD trigger boards [0] are just great for purposes like this. They are cheap and available with either a preset voltage like the author seems to use, or semi-fixed voltage selection (by putting solder-bridges on number of open connections/pads) or - very useful for tinkering - with a set of tiny switches that allow to change the voltage in a few seconds.

I think they are very recommended to have in your parts drawer if you like playing with electronics.

[0] “trigger boards” because they don’t do anything directly with the voltages and power. They only negotiate with the power supply which combination of voltage and maximum current (and therefore power) it should provide.

The markings "GND" "IGN" and "BAT" evoked something automotive, and a quick look at the manual reveals that this router was indeed designed with that in mind:

https://www.cisco.com/c/en/us/td/docs/routers/access/800/829...

The IR829's we use at work are absolutely remotely accessible and configurable, with no user interaction. They include GPS and cellular antennas, and with the correct credentials can be viewed through Cisco's IoT web platform.

In other words, I would never in a million years trust these second-hand. Best case is the org sunset it properly, worst case is when their data breach becomes a back door into your network, complete with current location.

Is the cellular modem removable, e.g. in M.2 slot?

Provided that isolation is not required... it be nice if there is a 'type-c power/data router' where you can plug multiple devices to and get both power and data though. The box itself just needs to have a gigabit port and a power port.

Requires device makers to make port be both PD and at least USB ethernet host. The router perhaps can try simulating usb ethernet gadget or something.

I don't like how it is a fire hazard though. What an earth, maybe the Cisco will run a self-test every year to check out something and it burns down, because the author used 3.25A board for 6A max drawdown. I hope at least he configured the 24V and then the 6A is just 3A probably.

The power profiles include a maximum current. If the device exceeds the current draw for the chosen profile, the power supply cuts the power.

The wikipedia article might be more accessible than the spec: https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver...

> draws 6 amps max

What kind of router needs over 100W to run? Does it expect to do PoE on every line?

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