Unruh wrote: > Just looked it up. A bit bizarre-- power over the ethernet? The ethernet > has no power supply capability. Do you mean that you have to supply the > device with 60V running on one of the unused ethernet cable lines? Sounds > noisy to me. > I believe it is a relatively new, but very real, standard. The power is transmitted as a phantom between two pairs. In one variation, they are the pairs used for normal, 10baseT. I gather one reason is that there are exemptions in electrical codes for ELV power feeds as part of datacommunication systems, whereas a normal feed would require a formally qualified (not just competent) electrician.
The feed is 48V DC. I'm not 100% sure that counts as ELV, but it is the same as most analogue telephone systems. The apparent source specification is IEE 802.3-2005, although I haven't gone to source. As the power is common mode with respect to the signals, the noise should not be excessive. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
