..........Software ISDN Audio Codec for PC
...............Software Audio over Network for PC
........Software Audio over DSL, ADSL and Internet

1. Check the CPU Load

• Communicator shows the current percentage CPU load on your system during connections and while idle.
• The idle figure should be less than 5% and certainly no more than 10%. If the idle figure is high, you should check if you have any other applications running in the background and close these.
• Whilst connected, up to 70-85% usage is fine. The exact figure depends on the machine. However if your machine react slowly when you press 'Disconnect' for example, this shows that the system is being run to its limit. If you are running other applications at the same time, try closing these down.
• Some audio cards and drivers use a large amount of CPU time to record and play audio - this is true of some older cards or really low-end hardware rather than newer or higher quality units. Try upgrading drivers, but you may need to change the card.
• AudioTX has been tested on a minimum spec PC which was a Pentium (I) 300 mHz with 32mb memory in Windows NT and 64mb in Windows 2000/98, but these really are absolute minimum specs and we recommend a P II 400 as a minimum.
• If your system is running at the margins, setting the MPEG-2 audio coding to 'Fast Coding' in the Audio Settings window may help. (This window is accessed from the View menu).

2. Check the Audio Buffering in the Audio Settings window

Some audio cards require more careful handling - if you are hearing regular but small clicks and skips, you can increase the latitude given to these cards in small stages to try and get rid of the problem.

• Try and determine whether the clicks and skips are appearing in the audio you receive, the audio you send or both.
• To fix clicks in the audio you receive, increase the setting of the 'Playback' slider one notch at a time and try connecting again.
• To fix clicks in the audio you send (received and heard at the other end), increase the setting of the 'Recording' slider one notch at a time and try connecting again.

3. Check that the card is able to record and play audio at the same time in another application without these glitches

• There are several audio programs which will allow you to record and play audio simultaneously
• CoolEdit Pro or CoolEdit 2000, S'ekd or CuBase can all be used and are all available as free downloadable demos
• As a last resort, you can even try starting to record in Sound Recorder (a windows app) - but remember to set the sample rate to 48kHz first - and then start playing audio with media player at the same time.

4. Close CD Player and suspend or close down any Virus Checkers

CD Player is notoriously bad at hogging your CPU and Virus Checkers may decide to do a full Hard Drive scan in the middle of the most important broadcast of your life!

Some sound cards are unable to use different sample rates for recording and playing full duplex. Ordinarily this is solved without you even noticing - AudioTX uses a sample rate converson process internally for these cards.

The problem occurs where a sound card claims when Communicator queries it that it does have the capability onboard, but in fact does not!

You can get around this by turning on 'Sample Rate conversion' in the Audio Settings menu. However you should only check this box when you need to use the different tx/rx samplerates as on some cards it will slightly reduce audio quality. If this is the case, the quality is only reduced on the lower sample rate side - which is normally only being used as the cue feed in any case rather than on the transmission side.

In the connection window, it shows 'ISDN not available' and I can't dial.

1. This error message normally means one of the following:

• You do not have an ISDN card installed
• You have installed an ISDN card but not the drivers
• You have installed the card and drivers, but there is no CAPI 2.0 driver present

If you think that you have correctly installed the card and drivers and the CAPI 2.0 driver was installed as part of that or you did so seperately, check the following: Look for a file called CAPI20.DLL in your Windows, Windows\System or Windows\System32 directories. If it's missing, then you have not got CAPI 2.0 installed.

Eicon Diva cards under Windows 2000 - the standard driver CD supplied with Eicon Diva cards does not always contain CAPI drivers - however you can download these from the web at http://www.eicon.com.

AVM cards always install the CAPI 2.0 driver as part of the main installation.

2. Have you previously had an ISDN card installed in this machine and since installed another card?

If so, you may need to manually remove all traces of both drivers and the CAPI20.DLL file and any other related ones like CAPI.DLL or CAPINT.DLL from the directories listed. Then reboot and check that all files are still not there. Then reinstall your new card.

3. Not all ISDN cards do support CAPI 2.0 fully

• Check that the card you are using does claim to support CAPI 2.0
• You can further check that it is capable of BTX or Bit Transparent connections
• The AVM and Eicon cards are generally the best - they're reliable, fuss free and not particularly expensive.
• You can always ask us if we have any experience with a particular card...

1. Are you or is another application set up to answer calls on your ISDN card?

Try closing any other applications such as voicemail systems or internet connections that might be using the same ISDN card.

Check that you are not using your ISDN line for anything else... e.g. making a telephone call or sending a fax

2. Have you correctly selected an audio card input and output in the main window?

Check that there is an input and output device showing next to the volume sliders in AudioTX. If there isn't, click on the select buttons next to each and make a selection. This is explained in full in Section 1 of this manual.

1. Check with your network administrator whether there are any restrictions on traffic across certain port numbers (AudioTX uses 5003 by default)

2. If you are entering a computer name rather than an IP address in the Address field, try an IP address instead. If this now works, you need to ask how the WINS lookup or DNS works on your network.

3. Are you able to ping between the two computers?

Ping is a DOS command line program which checks basic connectivity.

Open an MSDOS box inside windows on either of the PC's (Command Prompt) and type: PING 10.10.10.23 where you replace the 10.10.10.23 with the IP address of the other machine.

1. How busy is the network?

If you can see the hubs and routers, watch the lights and see if the drops correspond with peak traffic levels

2. Have you tried increasing the network safety margin?

If you are using a 'Dedicated Network' type connection, try the plain old 'Local Network' type of connection. This increases the delay by 100-200 ms but will allow you to see what the problem is.

If this fixes your problem, using a switched connection rather than a hub may help, or you could move the AudioTX PCs onto a quieter spur of the network.