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So the charger won't work without the data wire and it could destroy the laptop. It's so crazy because I've seen in these tech communities people saying it's re

So the charger won't work without the data wire and it could destroy the laptop. It's so crazy because I've seen in these tech communities people saying it's recommended to cut the data wires and everyone is upvoting it. I guess that's another popular misconception going around that it's generally fine to cut a data wire.

gnabgib 2y ago
The charger will work, just at a low/slow power. No destruction, unless it's non-conformant (the source should only increase the volts/amps if it detects the correct signalling from the drain... and this should is defined in the USB certification specs). You may want to charge without a data-wire, or use a cable with a correct power-negotiation chip if you don't know/trust the source (eg a charging nook in a library/school/bar/airport.. anywhere public). Some devices are very trusting of power sources, or have been (security is improving, modern phones require unlock before they even acknowledge they accept/send data).
- Faaak 2y ago
  USB PD without signaling won't work. It wont supply the needed voltage (e.g. 19V), and the laptop won't charge
  - yread 2y ago
    Is that true? I have a cable here that I use to charge my laptop with 65W PD but it doesn't make a data connection. Does it do some black magic?
    - Kirby64 2y ago
      There’s data, but then there’s also the “CC” pins. CC is mandatory for USB-C. It is what does the communication for PD. So, it’s data, but a very specific type of data.
    - cesarb 2y ago
      > I have a cable here that I use to charge my laptop with 65W PD but it doesn't make a data connection. Does it do some black magic? The magic is that USB-C has not one, but _several_ mostly independent "data" connection wires. Chargers normally do not use or care about the USB 2.0 data channel (or the separate USB 3.0 data channel), they only care about the separate "configuration" channel used for USB-PD negotiation; IIRC, according to the standard pure chargers are even supposed to short together the USB 2.0 wires, to signal to older USB B or micro-B devices "I'm a dumb passive charger which can provide more than just 2.5W of power". So, if you have a broken cable which does not have the USB 2.0 wires connected (which AFAIK is not allowed by the standard), but has the power and configuration wires correctly connected, it might (or might not) work as a charge-only cable.
- nucleardog 2y ago
  > You may want to charge without a data-wire, or use a cable with a correct power-negotiation chip if you don't know/trust the source (eg a charging nook in a library/school/bar/airport.. anywhere public). There's an alternate charging interface you can use that's pretty widely available and I'd highly recommend--the 120/240VAC outlets all over the place! Yeah yeah, I'm only half kidding. If you're going out to the bar you're probably not gonna shove a USB charger in your pocket. But in most of the rest of those situations (library, school, airport) and more you _probably_ have a few things you're carrying with you. Just leave a small adapter and cable rolling around the bottom of your bag and you don't have to worry about this. (Or at least you're into the realm of _wildly_ theoretical attacks.) This doesn't just avoid the potential security issues... A lot of those charging lockers and things are not exactly well designed or well engineered. If you use your own charger you also know some weird cheap out-of-spec setup isn't going to damage your phone and there won't be any incompatibilities with the charger/cable/device that leave you charging at 7.5W.
nixosbestos 2y ago
> I've seen in these tech communities people saying it's recommended to cut the data wires and everyone is upvoting it Right, and what communities are those, exactly?
marcosdumay 2y ago
The data lines weren't used for charging until fairly recently. Al of those people may not be up to date, or you may be seeing old discussions.
- cesarb 2y ago
  > The data lines weren't used for charging until fairly recently. Several proprietary protocols (like Quick Charge) used the data lines to negotiate the power and voltage, then USB Battery Charging standardized a way to indicate being a charger through the data lines, and that was all before USB-C. So unless you were satisfied with very slow charging, the data lines were always necessary.
throawayonthe 2y ago
[dead]
dragonwriter 2y ago
No, the charger will work fine – and at full power. GP is incorrect, the data lines are not used in power negotiation.

gnabgib 2y ago

The charger will work, just at a low/slow power. No destruction, unless it's non-conformant (the source should only increase the volts/amps if it detects the correct signalling from the drain... and this should is defined in the USB certification specs). You may want to charge without a data-wire, or use a cable with a correct power-negotiation chip if you don't know/trust the source (eg a charging nook in a library/school/bar/airport.. anywhere public). Some devices are very trusting of power sources, or have been (security is improving, modern phones require unlock before they even acknowledge they accept/send data).

Faaak 2y ago
USB PD without signaling won't work. It wont supply the needed voltage (e.g. 19V), and the laptop won't charge
- yread 2y ago
  Is that true? I have a cable here that I use to charge my laptop with 65W PD but it doesn't make a data connection. Does it do some black magic?
  - Kirby64 2y ago
    There’s data, but then there’s also the “CC” pins. CC is mandatory for USB-C. It is what does the communication for PD. So, it’s data, but a very specific type of data.
  - cesarb 2y ago
    > I have a cable here that I use to charge my laptop with 65W PD but it doesn't make a data connection. Does it do some black magic? The magic is that USB-C has not one, but _several_ mostly independent "data" connection wires. Chargers normally do not use or care about the USB 2.0 data channel (or the separate USB 3.0 data channel), they only care about the separate "configuration" channel used for USB-PD negotiation; IIRC, according to the standard pure chargers are even supposed to short together the USB 2.0 wires, to signal to older USB B or micro-B devices "I'm a dumb passive charger which can provide more than just 2.5W of power". So, if you have a broken cable which does not have the USB 2.0 wires connected (which AFAIK is not allowed by the standard), but has the power and configuration wires correctly connected, it might (or might not) work as a charge-only cable.
nucleardog 2y ago
> You may want to charge without a data-wire, or use a cable with a correct power-negotiation chip if you don't know/trust the source (eg a charging nook in a library/school/bar/airport.. anywhere public). There's an alternate charging interface you can use that's pretty widely available and I'd highly recommend--the 120/240VAC outlets all over the place! Yeah yeah, I'm only half kidding. If you're going out to the bar you're probably not gonna shove a USB charger in your pocket. But in most of the rest of those situations (library, school, airport) and more you _probably_ have a few things you're carrying with you. Just leave a small adapter and cable rolling around the bottom of your bag and you don't have to worry about this. (Or at least you're into the realm of _wildly_ theoretical attacks.) This doesn't just avoid the potential security issues... A lot of those charging lockers and things are not exactly well designed or well engineered. If you use your own charger you also know some weird cheap out-of-spec setup isn't going to damage your phone and there won't be any incompatibilities with the charger/cable/device that leave you charging at 7.5W.

nixosbestos 2y ago

> I've seen in these tech communities people saying it's recommended to cut the data wires and everyone is upvoting it Right, and what communities are those, exactly?

marcosdumay 2y ago

The data lines weren't used for charging until fairly recently. Al of those people may not be up to date, or you may be seeing old discussions.

cesarb 2y ago
> The data lines weren't used for charging until fairly recently. Several proprietary protocols (like Quick Charge) used the data lines to negotiate the power and voltage, then USB Battery Charging standardized a way to indicate being a charger through the data lines, and that was all before USB-C. So unless you were satisfied with very slow charging, the data lines were always necessary.

throawayonthe 2y ago

[dead]

dragonwriter 2y ago

No, the charger will work fine – and at full power. GP is incorrect, the data lines are not used in power negotiation.