Confirming operation of a QOR via use of the internal serial port

Updated by Bryan Jones


This document will instruct you on how to use the internal serial port on a QOR16 or QOR32 to confirm if the unit is booting. This procedure requires disassembly of the QOR as well as the need to build a special serial cable. This serial cable connects to a three-pin header inside the QOR.

This document covers the following Telos part numbers;



For this procedure you will need the following;

  • #2 Phillips screwdriver
  • 3 mm Allen wrench
  • Special serial cable 

Building the Cable

This picture shows the serial cable that is required. This a standard DE-9 Female connector on one end and a three-pin connector on the other that connects to the main board of the QOR. The connector on the mainboard is a standard 0.1 spacing connector.

I found this cable at a used computer store and modified one end adding the DE-9 connector.  Use any connector that fits over the pins without damaging them.

A good source for this cable is a Futaba 12 inch servo extension cable. It is a good length, and one end can be removed and fitted to a proper DE-9 connector per the pinout guide. A Google search for “Futaba servo extension cable” should yield many results.


The pinouts for this cable are as follows;


Board Header

Pin 2

Pin 1

Pin 3 

Pin 3

Pin 5

Pin 2

The following procedures require you to remove covers and other parts that are placed there for safety. Disassembly and service should be performed with all power disconnected and only by qualified personnel.

Cable Usage

Remove the cover from the QOR by removing the Phillips head screws from the top of and two sides of the cover, as well as the top two 3 mm Allen head screws from the front of the QOR.

Header Identification

Locate the two sets of Red and Black Power wires that plug into the mainboard. One is for mains power, and one is for back up power. The serial header is located near these connectors and is labeled J3 TERMINAL. Note that the small white triangle indicates PIN 1. The red arrow in this picture is also pointing at PIN 1 of this serial header.

The power wires are disconnected in this photo for clarity of the Terminal connector but are normally connected thru this hole to the mainboard.

Header Connection

Connect the serial cable noting the orientation of PIN 1 on the header to PIN 1 of your cable. Connect the other end to any standard RS232 serial port on your computer. You can use any serial port program, including Putty, which can be downloaded from here or search the web for "putty".

Session Connection

This picture shows proper settings for using Putty.  

In this test, the serial port in use was COM3.  Make sure you know what serial port you are using on your computer to connect to the QOR and replace COM3 with your COM port as needed. 

Once you have your cable hooked up to both the QOR and your computer, you can click the Open button on Putty. It should open up a terminal window and probably show you nothing other than a blinking cursor. If a window opens and then quickly disappears after you click Open, you have chosen an incorrect serial port. You can use Windows Device Manager to confirm what serial ports are in use on your computer.

Verification of QOR Operation

Power up your QOR. If you have removed the power connectors to gain access to the serial header, reconnect those and plug the QOR into power. If your QOR is working, you will see the following messages scroll by;

CPU & peripheral init.
Flash autodetect: part id=8821
Init Marvell 88E6095 switch @ 16
Platform: Cobalt
CPU: Coldfire 5274
Built: Jan 27 2011 @ 18:53:57
Monitor RAM: 0xc00000-0xd081ac
Application RAM Base: 0x200000
MAC: 00:50:C2:80:00:01
BootSelect=0 (hit ESC to enter monitor, BS to skip JFFS.)
JFFS2 partition at 0xff760000, size 0x880000
Current MAC is: 00:50:c2:90:00:66
Current Boot is: bank 2
Booting from partition 3
DEBUG: Partition 3 is at 0xff3c0000
S/W Bank 1915991 bytes
Decompressed 3957760 bytes
Linux version 2.6.28 (oleg@orthus) (gcc version 4.5.2 (Sourcery CodeBench Lite 2011.03-97) ) #22 PREEMPT Tue Mar 12 18:48:56 EET 2013

Wait for the scrolling of the message to stop. Generally, it will take less than 1 minute. Once the scrolling of messages stops, you should be able to press the enter key, and you will be presented with a prompt that looks like this;  

/ #

You are now at the standard Linux command prompt.

Perform this test first on a known working QOR so that you can confirm that you have built the cable and configured your serial program on your computer correctly. From there, you can test other QOR for proper operation.

If you have confirmed proper cables and settings and you get no response from the QOR when booting, likely there is a hardware problem, and the unit will need repair.

Also, note that there are built-in GPIO and Audio Loopback testing that can be performed to confirm proper operation of all GPIO and Audio inputs and outputs.  This is covered under a separate document and requires a special GPIO tester for testing GPIO and special audio cables for testing Mic inputs. Schematics for these cables are available by following the links to the documents if you have an interest in building them.  We do not offer these as pre-built cables.

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