✧✦Catherine✦✧Feb 28

pov: you wake up to receive a package with a vacuum chamber and discover that the vendor is a crackhead and a menace to society

this is a vacuum chamber. the power supply that comes with it has a type-C connector and it puts 12V on Vbus unconditionally. the pump works off both 5V and 12V, so it can pull vacuum off a normal type-C power supply. but the solenoid release valve (that lets you open the chamber once you're done) requires their illegal type-C-shaped power supply. also, not only does the chamber not support PD negotiation, it does not even have a CC pulldown.

to add insult to injury, it's using a NEMA 1-15P plug.

Show threadgroff 🇺🇦Feb 28

@whitequark

But the EU said everything had to have a USB connector.

Show thread✧✦Catherine✦✧Feb 28
@geoffl this is not a USB connector. this is a USB-shaped connector. there's a big difference
Show threadRob RicciFeb 28
@whitequark @geoffl I have a device that delivers 12v power via a 2.5mm audio connector and I wonder what audiophile hurt this person
Show threadRootWyrm 🇺🇦Feb 28

@ricci @whitequark @geoffl man, I got you all beat.

You are faced with a PC that has two cards with 4 RJ45 ports on them. Surely that's quad ethernet, right?

NOPE!
2 ports of 100baseT with bypass.
And 8 ports of RS232 running at 15V!

Extremely expensive hilarity ensues.

Show threadAndrew ZonenbergFeb 28

@rootwyrm @ricci @whitequark @geoffl Cisco RS232 is very much a thing, quite common in networking gear.

But if properly designed it and Ethernet can be mated nondestructively. Passive PoE probably not. But regular Ethernet shouldn't hurt RS232 and vice versa if actually spec compliant design.

Show threadRootWyrm 🇺🇦Feb 28

@azonenberg @ricci @whitequark @geoffl oh, you sweet summer child, the 100bT with bypass should have been your first hint.

When you dump 15 volts from 4+ sources into an early 100bT *hub*, good things do not result.

When you dump 15 volts into a 100bT hub *AND* your 3640's Ethernet port instead of it's console port, TAC is not amused.

When you dump 15 volts into the PRI interfaces, they do not care. Till you're sending on pins 7 and 8. Then they care a *LOT*.

Show threadΚέχ (👻🏴‍☠️)Mar 1
@rootwyrm @azonenberg @ricci @whitequark @geoffl What curséd magnetics-free shit are we talking about here? I've only been doing networking since 1997, but can't recall seeing any likely candidates. Everything I can recall would've been fine with the amount of current your typical MAX232/knockoff can swing with its adorables little charge pump.
Show thread✧✦Catherine✦✧Mar 1
@xek @rootwyrm @azonenberg @ricci @geoffl isn't MAX232 capable of sourcing like 50 mA+ of current through that dinky little charge pump somehow? or am I misremembering?
Show threadΚέχ (👻🏴‍☠️)Mar 1

@whitequark @rootwyrm @azonenberg @ricci @geoffl TI's datasheet says ±10mA, and the voltage/load-Z graph in Fig 5-1 makes me think that's being generous. (SLLS047N, p5, "5.6 Electrical Characteristics, Driver" and p6 Fig 5-1)

I suppose there's ~15µC of charge on the caps that could be dumped all at once when you plug a cable?

But, I dunno, I've swapped Fast Ethernet and console cables plenty of times without any problems. Aside from my life being slightly shorter due to the stress of not having a recent enough backup of the configuration for business-critical gear which has gone totally non-responsive.

Show thread✧✦Catherine✦✧
@xek @rootwyrm @azonenberg @ricci @geoffl thanks, I misremembered then
Mar 1 at 1:53amWeb