extending USB extension over cat5 cable

Three things on running USB over Cat-5 wiring:
1. On the RJ-45 8-pin jack, you want to avoid pins 1,2,3,6 because if it accidentally gets plugged into a switch or PC Ethernet jack, the 5-volts could fry something.

2. You want the power (+5v,ground) on the same color (blue,blue-stripe) so it doesn’t make an electronic field that can ruin the valuable data lines. the phone company runs 24V to our homes on one twisted pair of wires and it works fine.

3. Twisting the two data lines on one color (brown,brown-stripe) will keep data integrity over a longer run of lines. Ethernet lines do that and it works just fine.

I suggest the following from the USB to the Cat-5 jack:
1. usb pin 1 (+5v,red) goes to RJ-45 pin 5 (blue-stripe)
2. usb pin 2 (d-,white) goes to RJ-45 pin 8 (brown)
3. usb pin 3 (d+,green) goes to RJ-45 pin 7 (brown-stripe)
4. usb pin 4 (ground,black) goes to RJ-45 pin 4 (blue)

Using this configuration, you could simultaneously run Ethernet to a hub AND your USB extension with splitters and all.

trx audio over IP utility

Can I get this working?!


Download and unzip the source.

Add these packages to meet dependencies:

sudo apt-get install libasound2-dev libopus-dev libopus0 libortp-dev

There is no configure file so straight to ‘make’

then ‘make install’.

markp@lenovo:~/mark@pengelly.info/liskeard_fm/software for PCs/TRX/trx-0.2$ sudo make
cc -MMD -Wall -c -o rx.o rx.c
cc -MMD -Wall -c -o device.o device.c
cc -MMD -Wall -c -o sched.o sched.c
cc rx.o device.o sched.o -lasound -lopus -lortp -o rx
cc -MMD -Wall -c -o tx.o tx.c
cc tx.o device.o sched.o -lasound -lopus -lortp -o tx
markp@lenovo:~/mark@pengelly.info/liskeard_fm/software for PCs/TRX/trx-0.2$ sudo make install
install -d /usr/local/bin
install rx tx /usr/local/bin
Seems OK!

pcmcia 3com network card pinout for nec mt1065 projector

I’ve had a few pcmcia network cards floating around but lost track of which ones work to give the web control access for the NEC MT1065 projector.

Despite buying the correct wireless card I never got that to work in the projector.

The 3com 3CCE589ET works OK, (maybe the 3CCE589EC as well, but untested). Both these are 10Mbps cards. The 3CCFE575BT card doesn’t work (10/100Mbps).

The cards are cheap on ebay but often without the needed network cable. Original cable (I think) is PN: 07-0362-000 Can’t see any on ebay. However I have been able to source a similar 07-0383-000. These cables have no dongle, just straight wired through to an RJ45 plug.

The pinout for these is (I think) the same:

The card connector is a 15 pin connector.  Looking at the connector from behind, counting from right to left:

pin 1 = RJ45 6 (orange)

pin 2 = RJ45 3 (white/orange)

pin 3 = RJ45 2 (blue)

pin 4 = RJ45 1 (white/blue)

pin 7 = connector’s LED (polarity unknown)

pin 13 = connector’s LED (polarity unknown)


The connector on cable 07-0362-000 can be dis-assembled if needed and soldered

The connector on cable 07-0383-000 is more of a moulded unit, harder to break open I suspect.

Some of the 10/100 cables could be utilised, for the above. Many have the dongle bit (with safety transformer in it?) but no worries, just snip it off and connect an RJ45 connector instead of the dongle and resolder as above within the connector. Eg cable 07-0337-002 has the connector type that could be opened up and soldered if you had to doctor one from the newer 10/100 cards. I don’t think these pinout the same as the previous un-dongled ones though as i did try and use one of these with the 10Mbps cards, no joy. As of 2016 these 10/100 cables are on ebay a bit.

Don’t blame me if this is wrong!

thompson router with freedns.afriad.org

I need to create a dynamic dns rule in a thompson technicolor router. Problem is the ‘custom’ dns settings don’t let you actually change their default dns server. people have found they can telnet into the router and change the settings at the command line: see here

1. Telnet to the router IP address (normally

2. Log into the router using appropriate login details (if unknown, try Username: Administrator, and no password)

3. List the current Dynamic DNS options
dyndns service list

4. Modify the custom option using this command:
dyndns service modify name=custom server=freedns.afraid.org port=www-http request=/nic/update updateinterval=7200

Replace values appropriately
server – the domain name of your Dynamic DNS provider
port – www-http
request – /nic/update [the path at your Dynamic DNS provider for DNS update calls]
updateinterval – number of seconds between updates from your router – default is 86000 (1 day)

5. Save changes to the router

streaming test

This is a test to tryout our streaming server and see if the embdded player will work OK.
If you are a tester let me know!

remote vnc desktop

It’s not as easy as you might think to setup a remote desktop from boot in Xubuntu.

This is probably because these apps are called ‘desktop sharing’ apps, really aimed at desktops that are logged in and running. It’s also because it is a potential security hazard to have your VNC server running and ‘out there’ as soon as it boots up.

However, with appropriate security precautions (eg vpn access to the network) it can be done, relatively simply. It’s ideal for remote servers that you might need to reboot, that need to have a graphical environment installed.

I used this article. Although it didn’t work straight away that was because the text USERNAME  in the /lib/systemd/system/x11vnc.service file needs changing to the user name you’re using (duh).

command ps -ef | grep [x]11vnc on a remote ssh terminal (on the same network) will tell you if the service is up and running.

After years of faffing this works. I’m using x11vnc and the init (upstart) process for getting the server running from boot. This is on an Xubutnu 15.04 64bit machine