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What is theBridge?

Thebridge is an iLink/EchoLink compatible conference bridge that runs under FreeBSD, Linux, QNX, Windows and hopefully most other Posix compatible operating systems.

If you've never hear of EchoLink then this software probably won't make much sense to you. See: then if you are still interested continue here.


  • Compiles and runs on FreeBSD, Linux, OS X, QNX and Windows.
  • Daemon mode program with logging to syslog.
  • Forwards voice and text mode packets to conference members.
  • Displays members list with indication of who's talking.
  • Use GNU autoconfig tools for portability.
  • Provides test feature to assist users with level settings.


Q: How many users does thebridge support?
A: That depends primarily on your connection to the Internet. There are no preset limits on the number of users other than the setting of MaxConferenceClients in the configuration file. Approximently 17k bits per second of bandwidth are consumed outbound per user. Since the usual case is that only one single user is talking at a time the inbound bandwidth requirements are must less. The current documented record user count is 63 on the K5JD server during the 9/11 commemorative net. With 63 users the bandwidth was 1076k bits/second.

Q: Is there a Windows version?
A: Yes. This question probably means you think thebridge is a DOS program and are asking if a typical Windows graphical version of thebridge is available. The answer to that question is no. Thebridge is designed to be portable and runs under FreeBSD, Linux, Mac OS X, Qnx, and yes Windows (but not DOS). I am NOT planning on creating a Windows specific version that provides a more typical GUI.

Q: Is there any sound support, can I listen to the conference while I run thebridge?
A: Sorry No. Currently thebridge only deals with the data at the packet level, what comes in goes right back out. The data is never decoded into audio. Thebridge is designed primarily to be a system daemon, that is a background system process that just runs QUIETLY in the background. You'll need a client program *and* multiple external IP addresses to be able to listen to thebridge.

Q: How come none of the commands work? When I type on the keyboard nothing happens!
A: The commands are entered from the EchoLink client on the message line, not from the host. i.e. The commands are for remote use (both by users and administrators). Unfortunately if you are running thebridge locally and only have a single IP address there's no way for you to connect to thebridge using EchoLink. You can't even run EchoLink on the same host as thebridge. Thebridge is really designed to be run as a daemon under FreeBSD or Linux. I need to do some more work to make it a bit more friendly to a Windows user.

Q: How come none of the commands work? I AM typing the commands on the message line!
A: All commands start with a period or dot. In addition the dot *MUST* be the very first character on the line. Try entering .Help, that is help. The commands work, honest! Commands were done this way to prevent interference with message line traffic.

Q: The instructions say to find the file thebridge.dsp and double click on it but there is not any such file can you help me?
A: Read the README a little slower next time. "If you've downloaded the prebuilt version of thebridge ( the following has already been done for you. Skip on to configuration..." If you don't have thebridge.dsp you have downloaded the .ZIP file containing the prebuilt executables for Windows. If you want to compile thebridge from source download thebridge-x.xx.tgz instead. You will also need to have Microsoft Visual Studio installed on your system for double clicking on thebridge.dsp to work.

Q: Who uses thebridge ?
A: A survey conducted on 10/30/02 found 30 groups running thebridge, 19 running on Windows, 10 running on Linux and one running on FreeBSD. The record uptime was 29 days which is very close to the length of time that the version of thebridge they were running had been released. Details are available.

Q: Is it possible to connect to thebridge from an IRLP system?
A: Yes it is if both thebridge and the IRLP node have been configured by the owners to allow such a connection.

On thebridge side set the configuration variable SF_Enable to 1 and set RTP_Pass to a conference password. Give the conference password to the IRLP node operators that you want to be able to connect.

NB: The conference password is the only thing that prevents the general Internet community from connecting to your conference using any VoIP package that supports either RTP or the Speak Freely protocols when thebridge is configured in this manner. It would be very unwise to publish the password openly. If additional security is desired DO NOT SET A CONFERENCE password and use the .allow command instead. The .allow command provides additional security by requiring an IP address match as well as allowing different passwords to be used for each system.

See the EchoIRLP Web site for scripts that can be used by IRLP nodes to initiate the connection.

Currently the following conferences accept IRLP connections: *TECHTALK*, *TACOMA*, *LI_NY*, *APRS*, *K5JD*, *MN_CONF*, *OK-CITY*, *SEATAC*, *SINBAD*, *UTAHGATE*, *VK3JED*, *WASH_DC* and *WX_TALK*. Please contact those node owners for passwords.

Q: What version of Windows does thebridge require?
A: Thebridge runs on any 32 bit version of Windows, i.e. Windows 95 and later. Users of early versions of Windows 95 may need to update Winsock (Windows TCP/IP protocol stack) to Winsock 2. The update can be downloaded free of charge from Microsoft's Web Site.

Q: What version of Visual Studio do I need to build thebridge?
A:You only need Visual Studio *IF* you want to modify the program. If you simply want to run it download instead which has already been built for you. That being said, I have the "Professional" version of Visual Studio 6, I don't know if anyone has ever tried to build it with the Standard Edition of Visual C++. I don't honestly know if it would work or not. If anyone has built thebridge successfully with the Standard Edition I would be interested in hearing about it so I can update the FAQ.
It would be FAR FAR cheaper to setup a FreeBSD or Linux system if you want to mess around with the code even if you have to build/buy a new computer. The full version of Visual studio retails for > $1000 although you can probably find older versions on Ebay for much less. Both FreeBSD and Linux come with all of the tools you need to build thebridge for FREE.

Q: How do you run multiple conference rooms on one host?
A: You'll need a host that has multiple public IP addresses to do it. If you have such a host:

  1. Create multiple configuration files, one for each instance.
  2. Use the Bind2IP configuration variable to bind each instance to a different IP address.
  3. Set WorkingDir for each instance to a unique directory.
  4. Set AppName for each instance to a unique name (tbd, tbd1, tbd2, etc...).
  5. Modify the startup scripts to specify the appropriate configuration file using the '-f' switch and start the appropriate number of copies.

Q: How do you setup thebridge to play a welcome greeting when someone connects to the conference?

  1. Assign an administrator password in your configuration file.
  2. Connect to conference.
  3. Login as an administrator (.admin command)
  4. Start recording a file (.record welcome.tbd)
  5. Talk to record your greeting.
  6. Stop the recording (.record stop)
  7. Add the recording to your bulletin list (.list add welcome.tbd test)
  8. Listen to the recording to see if you like it (.play 1)
  9. Repeat steps 4,5,6 and 8 until you are happy with the results.
  10. Delete the test bulletin (.list delete welcome.tbd)
  11. Add a line WelcomeFile = welcome.tbd to your configuration file.
  12. Reload the configuration file (.rehash)

Q: How do you debug thebridge ?
A: I use an automatic source code inspection system to check my code before attempting to debug it. The code anomaly trapper (CAT) finds the majority of the bugs before I run it. If you don't have one I highly recommend that you download one.

Wish List

  • Time stamps for every message line - Rex, ORLANDO conference.
  • Log the station call signs that log in and out - Rex, ORLANDO conference. [Added in version 0.44]
  • A way to 'allow' only certain stations to connect to the conference - John KR0Y. [Added in Version 0.42]
  • Delay the packet transfer in the beginning of each key up lets say for 1-2 seconds to prevent bounce? Maybe a toggle with a milisecond control for the admin.... - Len N2Len [Added in version 0.37]
  • Enable/disable the .lurk feature - NE2EI + a crowd of others. [Added in version 0.37]