3 ms·
Serbia (former Yugoslavia) was mostly in turmoil in the 90s, and while I did get online using dial-up in 1995, new tech was (very) slow to arrive: I used ISDN f
by necovek 3y ago
Serbia (former Yugoslavia) was mostly in turmoil in the 90s, and while I did get online using dial-up in 1995, new tech was (very) slow to arrive: I used ISDN for a few short years in early 2000s before ADSL finally arrived. It was amazingly reliable even in Serbia.
But compared to the regular 20V phone line, ISDN used something like 120V (which I learned by carelessly changing the connector like I used to on the regular phones), and in a country where power went out regularly, I wondered how much power could I get out of it for emergency situations.
- usr1106 3y ago20V? Germany has traditionally used 60V. The current spec allows 20V - 105V https://www.nostalgietelefon.de/beachten/1TR110-1%20Ausgabe%2008-2007_V110.pdf https://www.nostalgietelefon.de/beachten/1TR110-1%20Ausgabe%...
- 65a 3y agoMa Bell used -48v DC in the US, which was backed by a giant lead acid battery at the local exchange. It was quite common to have ADSL circuits working during major power outages, so long as the modem and servers were on redundant power. It might still be worth coming up with a USB charger circuit, but I assume current draw is metered.
- ufocia 3y agoAnd 90V RMS AC to ring the bell on POTS lines.
- 65a 3y agoSure makes it easy to find the line on a 66 block
- usr1106 3y agoI don't think directly metered, but protected such that the line will automatically disconnect if there is more current drawn than usually.
- aspenmayer 3y agoI’ve seen COTS adapters which connect to a standard phone jack with pass through and provide one USB port, advertised as an emergency/backup power. I don’t know how much power they can draw, however. The one I’m familiar with is called: VR3 (brand) Phone Jack Powered Emergency Night Light & Charger (model: PJNL-USB)