8 ms·
Telephony has been using -48V as a line voltage for a very long time, probably > 100 years.
by bryanlarsen 2y ago
Telephony has been using -48V as a line voltage for a very long time, probably > 100 years.
- matrix2003 2y agoIs that for power deliver, or signaling?
- Kirby64 2y agoBoth. It powers old school telephones.
- p_l 2y ago-48VDC was standard for powering telephone equipment, and is also common standard for direct current datacenter connections. Signaling on POTS easily hit over 100V, btw.
- amanaplanacanal 2y agoI remember getting zapped when the phone rang when I was a teenager back in the 70's. Good times.