## Echo servers

Setting up Speak Freely usually involves fiddling around with different compression modes, connection options, and, perhaps, workarounds for bugs in your network and audio drivers. Getting everything set right for your machine, network connection, and audio hardware usually requires testing various modes in real connections. It's irritating to get lots of "Hello, can you hear me?" calls which consume 10 or 15 minutes of your time each as a total stranger asks you to report on various settings on their end.

Echo servers allow you to run tests on your own, 24 hours a day, without disturbing others. An echo server is simply a machine running a special copy of Speak Freely for Unix which, rather than playing audio it receives on the speaker, stores it in memory for 10 seconds and then sends it back to the machine which sent it, using the same compression and encryption modes. Before you experiment with an echo server, you might want to try local loopback to verify that your sound hardware is working properly before venturing onto the network.

To run a test, create a new connection to one of the echo servers listed below. Unless you deliberately want to experiment with long distance transmission, it's usually best to connect to a nearby server. Then select whatever compression and other modes you want to try and transmit a short (less than 10 second) test message, such as the traditional "Testing: one, two three, four" and go back to receive mode. Ten seconds after the start of your test message, plus however long it takes the network to transmit the sound in both directions, you'll hear your test message returned by the echo server. If the audio is broken up, you may have to select different modes (or it may simply indicate traffic on the network between you and the server is so congested everything is being delayed).

A public Speak Freely echo server is available at the site:

            echo.fourmilab.ch       Switzerland (see note below)

As with everything on the Internet, servers are in a constant state of flux. For up to date information on available echo servers consult the Speak Freely World-Wide Web page: http://www.fourmilab.ch/speakfree/windows/.

The echo.fourmilab.ch server shares its connection to the Internet with the busy Web site www.fourmilab.ch. As a result, you may get break-ups when testing with that site purely because the Web traffic has saturated the capacity of the site's Internet connection. Other servers may have similar constraints, which often vary with the time of day and day of the week.