- Switzerland - English
- Contact
Ethernet and power distribution
In addition to a data connection, each IP device also requires a power supply. Due to the frequent reloading or replacing needed, batteries are not considered a viable solution for permanently installed LAN devices. Two external power supply options have established themselves:
The main disadvantage of a separate power supply is the need for a separate cabling. This is why PoE is becoming increasingly popular. The IEEE has standardized this power supply method in the standards 802.3af (PoE), 802.3at (PoEP) and 802.3bt (4 Pair Power over Ethernet or 4PPoE).
See R&M whitepapers on PoE, PoEP and 4PPoE
Critical factors for PoE, PoEP and 4PPoE are the temperature increase in the cable due to power transmission, the destruction of the RJ45 contacts as a result of sparks when unplugging under load and the temperature increase in connectivity due to degrading contacts in the wire termination.
All R&Mfreenet components are suitable for use with PoE, PoEP, and 4PPoE applications. Products with especially reliable IDC termination are marked with the PowerSafe logo.
In addition to the right choice of cabling components, the planning and installation of the cabling system has a substantial influence on ensuring the successful implementation of Power over Ethernet. In recognition of this fact the international standards introduced the Remote Power Categories into their respective installation standards (i.e. EN 50174-2 and ISO/IEC 14763-2). 3 Remote Power Categories are defined: RP1, RP2 and RP3. The average allowed DC-current in any given cable bundle in the installation is defined and determines the RP category (the higher the more current allowed).
Details you can read in the Whitepaper “Remote Power Categories”.
To help its customers in the planning and installation of future-proof cabling, R&M introduced the RP categories into the R&Mfreenet warranty system.
With the help of the updated, well proven “PoE Calculator V3”, planner and installers are now able to document to the end customer the achieved RP category. Consequently R&M has introduced the RP categories also into the R&Mfreenet Warranty Certificat.
Every properly installed R&Mfreenet cabling system conforms to RP1. By supplying the planning documentation of the PoE Calculator together with the measurement data of the links, the RP categories can be upgraded to RP2 or RP3, respectively.
When using remote power supply (PoE), ensuring a low resistance unbalance is a precondition. Channels and components with too much DCRU will create problems in the transceivers of the Ethernet devices. Resistance unbalance testing ensures, that an installation supports PoE without introducing data transmission issues or unaccounted heating. Field testing is more important than ever to ensure low DC Resistance Unbalance. Patch cords should be included to the testing scheme, by performing channel testing.