How to use “FAKE” Micro USB Serial Port of Aruba Networks Access point with DIY Adapter



I hate the AP-5xx’s serial port. The AP-5xx series access points of Aruba Networks have the same serial console shape as the Micro USB Type B. For example, the Cisco Catalyst has a Mini USB Type B port and when connected to the PC with a USB cable, the Catalyst is recognized as a COM port and can be accessed. Because there is a USB-to-serial conversion chip on the Catalyst side. This means that Catalyst will recognize it as a USB device. But Aruba’s AP is different.

The Aruba AP-5xx’s configuration port is the same shape as the Micro USB Type B. However, there is no USB-to-serial conversion chip on the AP side. It looks like a Micro USB, but the signal is a 3.3V TTL. If you look at the specifications on the Aruba’s website, it says “Proprietary, micro-B USB physical jack”. “PHYSICAL”. I’d like to think that there is probably some kind of fail-safe circuit on the AP side, but there is a possibility that it will be broken if you connect an ordinary USB cable.
If you search with Amazon, you can buy the Aruba Micro-USB 2.0 Console Adapter Cable AP-CBL-SERU. The AP-CBL-SERU is about $30. I don’t know if I can afford to pay for such a non-universal cable.

The only thing I can praise is that the pin assignment of this non-Micro-USB port is open to the public. For example, if you look at Figure 7 Micro-B Port Pin-out in the Aruba 510 Series Campus Access PointsInstallation Guide, there are the following descriptions.

Aruba FAKE Micro-B Pin assign

That’s great. Since the pin assignment of the port is understood, and the level of TTL is described as 3.3V in the explanation of AP-CBL-SERU, the only thing to do is to make the AP-CBL-SERU like cable.

How to make

You need to prepare the materials first.

  • USB Type A to MicroUSB Type B Cable
  • USB-to-serial conversion board (the cheapest one is less than $2)
  • USB TypeA Female Connector
  • Jumper cable
  • Universal Board
  • Pin socket
  • Soldering iron and solder
  • Needle-Nose Plier
  • Flat blade screwdriver

In my case, I didn’t buy anything new for this article.
I got The USB TypeA female connector from The USB cigar charger that I had my home. I didn’t care about the USB connector from the original purpose, so I got it. I don’t know what the other stuff was, but it was bought.
First of all, I took apart the USB cigar charger and used a soldering iron to get the connector. It’s good to say “apart”, but actually is to destroy it. I used the Needle-Nose Plier and Flat blade screwdriver in this part.

Next, the USB connector and pin socket soldering to the board.


Finally, you can access the serial console by connecting it as shown below.
Wiring is TX/RX/GND only. When using a USB-TTL conversion board with a variable operating voltage of 5V/3.3V, set it to 3.3V before connecting. If you forget this, you may break it.

If you use it frequently for work, I think it would be better to buy a genuine cable that looks like a cable and is easy to use. However, if you want to use it tomorrow but can’t make it in time if you order it, or if you don’t want to use it so much that you have to pay for it yourself, I think this is enough.
Note that I bought AP-CBL-SERU, just in case I tried this conversion and success.

Good luck. Thank you.