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Cake day: June 11th, 2023

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  • You seal everything but the battery in one watertight compartment. The battery is a sealed, self-contained package, in a second compartment. Dunk the phone, the only thing that gets wet are the battery contacts, which are protected the same way that earbuds with magnetic chargers are protected: if the contacts get wet, the battery shuts itself off until it has been dried off.










  • It’s not the voltage you need to focus on. It’s the current.

    Analog telephone wiring used 90v @20hz to ring the phones. Off-hook, they were at 9vdc, which rose to 48vdc on-hook. The insulation can handle potentials much higher than 5v.

    But, telephone wires are typically 26awg to 22awg, which are only rated to .361 to .92 amps for power transmission. Pull too much current, and you risk melting the insulation and starting a fire.

    Since DC power (watts) are volts times amps, to keep the amperage low, you will want to keep the voltage as high as the insulation will tolerate.

    Telephone wiring is very similar to (and may even be carried on) cat5/6 cabling. There are formal standards for using cat5/6 cabling for power transmission: Power-Over-Ethernet standards 802.3af, 802.3at and 802.3bt. These standards call for 44 to 60 volt power injectors, and up to 15.4 watts per wire pair. If I were going to jury rig household telephone wiring for power transmission, I would use those standards as a guide.

    You should use a current-limited power supply, to keep your current below 0.361A, or you risk melting the insulation and starting a fire.




  • It’ll take you public IP and translate those packets to use your internal one.

    That is NAT, yes. But that is only one small function that a router can perform, and not all routers have NAT enabled. You only need NAT if your ISP only allows you to use a single IP address.

    If your computer has an address that starts with 169, 168, or 10 there is a NAT somewhere in your network.

    That’s not actually true. I can create such a network without connecting it to the internet, no NAT. I can create a second network, again, no NAT. I can then use a gateway router that allows any node on the first network to reach any node on the second. That router is still not doing any NAT. It’s just passing traffic between two networks.