plugable usb 2.0 ethernet adapter schematic

#Plugable usb 2.0 ethernet adapter schematic drivers
#Plugable usb 2.0 ethernet adapter schematic driver
#Plugable usb 2.0 ethernet adapter schematic full
#Plugable usb 2.0 ethernet adapter schematic mac

In the genuine chip, the 12MHz frequency would be used to derive 480MHz for USB 2.0 High Speed by using a PLL frequency multipler circuit. Thanks Gerard! So the cheapest ones they could be are around $0.40 each ( 12MHz/ 25MHz), the cheaper board's single crystal is then closer to 20% of the cost. I checked the reference schematic for ASIX's Demoboard and he's right.

#Plugable usb 2.0 ethernet adapter schematic full

Fixed!ĮDIT 2: Gerard points out in the comments that the two TXC chips are probably just crystal resonators (not full oscillators) as well. This wholesale cost alone is nearly the retail price of the cheap adapter on .īy comparison, a single large crystal resonator like the one on the cheap adapter costs $0.16 from the same source ( 6% 20%, see below, of the cost.)ĮDIT: Someone on reddit pointed out that I was using 'oscillator' incorrectly to refer to the large crystal, which is only the resonator part of an oscillator circuit. The Apple adapter has two 'TXC' brand oscillators (the shiny silver packages.) These cost around $1.33 each if you buy 15,000 4. The cheap adapter only has a single 25MHz crystal. The genuine AX88772A requires two crystal oscillators for accurate timing - a 25MHz oscillator for the ethernet interface clock, and a 12MHz oscillator for the USB interface clock. To know if it is a modified knockoff or made from scratch we could dissolve the chip packages in acid ('decapping' them) and then look at the exposed silicon die under a microscope. It might even be a brand new ASIC, created from scratch to be compatible. It's been modified to make it much cheaper to produce. They've been around since the early 80s, maybe earlier.

The biggest difference is this: the Apple adapter contains a clearly labelled ASIX AX88772ALF USB to Ethernet bridge, the other adapter has an unmarked chip that is not made by ASIX.ĪSIX don't make any USB/Ethernet devices in a 32 pin package, their smallest package has 64 pins, same as the genuine one above.Ĭloning ASICs isn't new to the computer world. Both adapters have an Ethernet transformer to isolate the ethernet signals from the rest of the board (MEC TM1701M & LFE8423, respectively.).Both adapters have a 512 byte EEPROM onboard (Atmel AT93C66B.) 3.It seems $29 buys you shielding from interference.

#Plugable usb 2.0 ethernet adapter schematic mac

Corp.Įth1: register 'asix' at usb-0000:0e:00.0-2.1.2, ASIX AX88772 USB 2.0 Ethernet, 00:8a:8d:8a:39:2bĪlso, the hardware MAC address prefix (00:8a:8d) isn't any known vendor OUI (organisationally unique identifier.) Seems odd, although chipset vendors (like ASIX) often require the device manufacturer to register their own OUI (for instance the Apple adapter uses an Apple prefix.) For a no-name vendor, it makes sense to just make one up. Usb 3-2.1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 The Linux kernel log says: usb 3-2.1.2: New USB device found, idVendor=0b95, idProduct=772a There are a few unusual things about the cheap adapter, though. By comparison, the builtin ethernet on my laptop measured 94.8Mbps (after being set from gigabit to 100Mbps.) Oddities The Apple adapter measured throughput of 94.3Mbps.

When I ran a TCP throughput test with iperf, they both performed well.

#Plugable usb 2.0 ethernet adapter schematic drivers

The cheap adapter comes with drivers for OS X & Windows, as well.

#Plugable usb 2.0 ethernet adapter schematic driver

In Linux they both use the driver for an 'ASIX AX88772A' USB to Ethernet converter, even though the Apple one reports as 'Apple' and is sold only for the MacBook Air.

The other is sold at Apple Stores for $29. One of them is sold on ebay for $3.85 AU ($3.99 US), including postage to Australia. Taking apart a very cheap USB to Ethernet adapter and pondering on the parts found inside.