About a year ago I purchased a cheap TDM410P clone from eBay. The pricing was just too cheap to refuse.

To compare the pricing:

• Digium Card with 2 x FXO, 2 x FXS = $637.78 USD + shipping
• Chinese Card with 2 x FXO, 2 x FXS = $84.94 USD inc shipping

One good thing is that these cards work straight out of the box with the dahdi drivers. From my experience, the FXO ports seem to work perfectly. The FXS ports however gave me no end of trouble.

So finally I decided to spend some time on it to try and figure out what is going on. Now on the documentation, for using these cards in Australia, there is a opermode switch that is passed as the module is loaded (for me, in /etc/modprobe.d/dahdi.conf): options wctdm24xxp opermode=AUSTRALIA

What I noticed is that when this was set, the noise levels on the FXS ports was unacceptably high. It was almost at a point where it started to drown out the dialtone! Interestingly enough, this ONLY happens on the receive side and the person on the other end can hear you fine.

To cut a long story short, I played around with the options available and I came across this combination: options wctdm24xxp latency=6 companding=alaw

Now the noise is just about gone (I would swear it is CNG now) and the audio quality is much better than before. Oh - and before I forget, as this changes the impedance on the line etc, make sure you run fxotune again!

On a side note, I would love to see Digium produce a much cheaper card to compete with the chinese cards - as really, they are a victim of their own success in the home / hobby market. Maybe a suggestion could be to offer a card with no support - but a warranty service. Sadly, I’ve dealt with Digium before (yes, I actually own some completely useless G729 licenses!) so I’m not expecting much to happen.

Hi all,

Well, I’ve started using Dropbox quite a lot now for my own syncing of stuff between PCs - as some are still on Windows XP - which doesn’t have a great method of syncing documents.

One thing I’d love is to grab a bit more space! As they give you an extra 500Mb for referring people, if you don’t have an account with Dropbox already, please use my referral link to sign up!

This is actually a good summary of how it all fits together… Worth a watch…

Its been a while since I’ve posted about my aviation training… Last week I finally managed to get that wonderful sticker in the log book for my Night VFR rating. Held up for months after having issues with aircraft, and mixing that with the variable Melbourne weather - its finally complete.

That is all.

Another round of updates just pushed out. Some of the mirrors are still syncing so you may have to be a little patient.

NOTE: You will need to upgrade to kernel-xen-release 6-3 or above to get these updates.

Kernel changes:

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* Mon Feb 20 2012 Steven Haigh <netwiz@crc.id.au> - kernel-xen-2.6.32.56-1
- Linux 2.6.32.56
  USB: ftdi_sio: fix initial baud rate
  USB: cp210x: do not map baud rates to B0
  USB: serial: CP210x: Added USB-ID for the Link Instruments MSO-19
  hwmon: (sht15) fix bad error code
  hwmon: (f71805f) Fix clamping of temperature limits
  USB: usbsevseg: fix max length
  usb: io_ti: Make edge_remove_sysfs_attrs the port_remove method.
  USB: cdc-wdm: updating desc-&gt;length must be protected by spin_lock
  USB: ftdi_sio: Add more identifiers
  USB: serial: ftdi additional IDs
  USB: ftdi_sio: add PID for TI XDS100v2 / BeagleBone A3
  USB: ftdi_sio: fix TIOCSSERIAL baud_base handling
  dm: do not forward ioctls from logical volumes to the underlying device
  block: fail SCSI passthrough ioctls on partition devices
  Revert "ARM: 7220/1: mmc: mmci: Fixup error handling for dma"
  crypto: sha512 - reduce stack usage to safe number
  crypto: sha512 - make it work, undo percpu message schedule
  drm: Fix authentication kernel crash
  eCryptfs: Make truncate path killable
  ecryptfs: Improve metadata read failure logging
  eCryptfs: Sanitize write counts of /dev/ecryptfs</netwiz></code>

Xen changes:

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* Thu Feb 02 2012 Michael Young <m .a.young> - 4.1.2-6
- Fix buffer overflow in e1000 emulation for HVM guests [CVE-2012-0029]

* Sat Jan 28 2012 Michael Young </m><m .a.young> - 4.1.2-5
- Start building xen's ocaml libraries if appropriate unless --without ocaml
  was specified
- add some backported patches from xen unstable (via Debian) for some
  ocaml tidying and fixes