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Jack PC Hardware User Manual - Training Department 
Version 0506 
 

 

Currenly there is a global standard for Power-over-Ethernet maintained by the IEEE. This 
standard identified as IEEE 802.3af and is accepted by all vendors.  

Unfortunately, before it was accepted there were other PoE detection methods that were sold 
by many vendors. These PoE methods called today  pre-standard. Detection method is the 
mechanism that PSE (Power Sourcing Equipment) uses to poll the the PD (Powered Device) 
to assure that the connected device is indeed a PD and is capable of receiving the power. 

In particular there are two main pre-standard methods:  

•

 

Bulk Capacitor (sometimes called PowerDsine method) – this method uses a big 
capacitor connected between the powered lines to identify a PD to the PSE. 

•

 

Cisco high frequency signaling – this method uses a high-passs filter between the 
TX and the RX lines to identify the PD. 

These two pre-standard methods are not natively supported by new equipment such as Jack-
PC. Chip PC currently develops jack installable mosules that will enable detection of pre-
standard PSEs. 

If PoE does not work and you suspect that your equipment is pre-standard – check the switch 
/ injector specification for detailed information. 

 

Some tips about Pre-standard PoE: 

•

 

In general every PoE equipment sold before 2002 is probably pre-standard. 

•

 

You can use the PowerDsine single port power injector (can be purchased as an 
accessory from Chip PC) to test your installation and confirm that wiring is OK. 

•

 

Some modular switches contains internal inline power modules (for example Cisco 
Catalyst 6500 series). In this case you can replace these modules to  802.3af 
modules to power specific Jack-PC connected ports. 

•

 

Some switches / PoE injectors supports both pre-standard and standard power. Make 
sure that these are configured properly for 802.3af and not pre-standard power.