PoE tester teardown

Here is teardown of one cheap power over Ethernet tester from eBay. It worked OK and did what it promised. It came with instructions that seem to be for a slightly different model witg more features. What is inside Circuit details. It has two sensing circuits: for end span and middle span power. I have

Ethernet in the first mile I came by a device with 2BASE-TL ports in it. Google search revealed that this standard was made by IEEE Ethernet in the first mile (EFM) working group. It standardizes networking techbologies for the customer’s point of view it is their “first” mile, although from the access network‘s point of view it is known as the “last mile“.  I know

Zyxel gigabit switch

I decided to replace my aging Zyxel and Netwjork 100 Mbit/s Ethernet switched with new gigabit models. I decided to get two ZyXEL GS-108S v2 Media Switch as replacement for those. The Zyxel GS-108S v2 10/100/1000 Mbps switch is designed to provide reliable high-performance media network connectivity – that’s what I need. The Zyxel GS-108S

Ethernet switch teardown

Here is tear-down of old Zyxel  ES-108 10/100Mbit/s Ethernet switch. I had one on my network for many years, but one day it stopped worked and started making whining noise. Look inside. Closer look to details. Main Ethernet switch chip is ADM6999 from ADMtek (now part of Infineon). In addition to it line transformers and power

Uusiteknologia magazine issue 2/2017

Newsest issue 2/2017 of Uusiteknologia magazine has been just published. The magazine has three technical articles written by me (Ethernet, Bluetooth Mesh and smart phone OS). The magazine is in Finnish language, but the technical articles have also short summaries written in English. You can read the magazine on-line or download in PDF format.  

Probing Ethernet cable with an oscilloscope

This article talks about measuring 10 Mbit/s (10Base-T) and 100 Mbit/s (100Base-TX) twisted pair Ethernet signals. Those standards use two wire pairs for the communications and use differential signaling. Differential signaling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals,

RJ-45 Ethernet surge protection

I have earlier written about Lightning protection and ADSL overvoltages and protection in this blog. And I have published several surge protection documents at documents section. What about Ethernet line surge protection? Ethernet ports as they are are pretty well protected as they are compared to many other computer ports: Ethernet ports are transformer