Q: What is ztalk?

A: Ztalk is a client and daemon that allow you to transmit voice broadcasts over the internet. A client, with a computer equipped with a recoding audio device (such as a soundblaster) can record a message, which is then compressed and trasnmitted to an aqaiting daemon in the recipient's computer. The daemon uncompresses and processes the message on their person's speaker/headphone device.

Q: What audio format does ztalk use?

A: Ztalk uses the Sun Audio (.au) format, which is used by the /dev/audio device for playback and record.

Q: What platforms support ztalk?

A: Though ztalk was developed on the Linux OS, ztalk has been successfully ported to SunOS, IRIX and a version for the NeXT is in the works.

Q: What are the hardware requirements?

A: First of all you need sound record and playback capability, such as a soundblaster, or native Sun audio support. You also need some form of internet connection, be it slip, ppp, ethernet or term (pseudo-slip). The faster the better of course. The main considerations are transfer rates and the ability to rapidly compress/decompress the audio files. A 486 and a 14.4k modem is ideal at minimum. (though it works, albiet slowly on a 386 with a 2400 baud modem).

Q: Where can I get ztalk?

A: The two most common sites are:

ftp://nermal.santarosa.edu:/pub/vot or sunsite.unc.edu:/pub/Linux/apps/sound

Q: Does ztalk work over term? (pseudo-slip serial link)

A: Yes, thanks to OKI and Albion (irc-nicks), ztalk has native term support

Q: Can anyone use ztalk?

A: Currently, ztalk requires that you have super-user access on a system to install and properly use. (Or a term-linked host). The ztalk daemon, ztalkd, requires installation in the inetd.conf file. Only one user per host is supported. Q: Who wrote ztalk?

A: Ztalk was initially birthed as 'mtalk' by Misch. Dane and Creon (Irc-nicks) acquired the source and modified and improved the sampling rate and sound quality, and added compression. This became known as 'ztalk'. Successive vresion have arrived with the help of Fein and Albion, who added a user shell and voice mail.

Q: What Voice Mail?

A: A feature that was added by Fein and Albion, Voice Mail is the logging of incoming Voice Mail by the daemon to a spool directory for later playback. This works much like an answering machine. The files are stored, date-stamped in /tmp/vmail (subject to change) in standard Sun audio format. Ztalk and Xztalk (X11 client) support Voice Mail playback. To use Voice Mail, you need at least ztalk-0.3.

Q: Is there a graphical client available?

A: Yes. Thaddeus has written an OSF/Motif-based client for the X windowing environment. This is available at: sunsite.unc.edu:/pub/Linux/apps/sound/talk/xztalk-*.tar.gz and offers native term support.

Q: What should my ztalkd /etc/inetd.conf entry look like?

A: This is a example, with some typical veriations: 

  ztalkd  stream  tcp     nowait  root    /usr/etc/ztalkd     ztalkd
  or
  ztalkd	stream	tcp	nowait	root	/etc/ztalkd	ztalkd
  or
  ztalkd	stream	tcp	nowait	root	/usr/sbin/tcpd	/usr/sbin/ztalkd
Compare one of these entries to other inetd.conf entries for which format is most valid. Be sure ztalkd is in the correct path.

Q: What should me ztalkd entry in /etc/services appear like?

A: This is what it should look like: 

  ztalkd          5109/tcp                        # ztalk
Q: How do I reset inetd so it accepts these modifications?

A: Do a list of your processes and find the PID (Process ID) of the inetd process: 

     % ps ux

     USER       PID %CPU %MEM SIZE  RSS TT STAT START   TIME COMMAND 
     root         1  0.0  0.0   48    0  ? SW   15:58   0:00 (init)
     root        34  0.0  0.0  296    0  1 SW   15:58   0:00 (sh)
     root         3  0.0  0.3    7   28  ? S    15:58   0:04 /etc/update
     root        35  0.0  0.0  306    0  2 SW   15:58   0:00 (sh)
     root        27  0.0  1.4   58  104  ? S    15:58   0:00 /etc/syslogd
     root        36  0.0  0.0   37    0  3 SW   15:58   0:00 (getty)
     root        31  0.0  0.0   64    0  ? SW   15:58   0:00 (inetd)
In this example, it is '31', now we 'reset' this process: 
     % kill -1 31
Q: How do I check if the daemon is working?

A: Test to see if the changes and such work, by telnetting to the ztalkd port: 

     % telnet localhost 5109

     Trying 127.0.0.1...
     Connected to localhost.
     Escape character is '^]'.
     001 cb server ready [ Away, Voice Mail Logged ]
It appears to be working.

Q: How do I get ztalkd to to work with term?

A: (ugh, you had to ask...) Install ztalkd normally as the instructions say to. To receive incoming ztalk messages, you need to redirect the remote host's 5109 port to your own. So, on the remote you will: 

      % tredir 5109 127.0.0.1:5109
(I use 127.0.0.1:5109 instead of 5109 because that's the only way tredir works on my specific system, and it's common with others.)

Test the connection by telnetting to the remote host's port 5109.

on remote: 

      % telnet localhost 5109

      Trying 127.0.0.1...
      Connected to localhost.  
      Escape character is '^]'.
      001 cb server ready [ Away, Voice Mail Logged ]
That indicates a healthy connection. Anything else is bad news.

Q: When telnetting to my ztalkd daemon as a test, I get 'Connection closed by fireign host' immediately, or 'Connection refused'.

A: Something has not been properly configured, either with /etc/inetd.cond, /etc/services or if you are using term, your tredir 

 "Connection closed by foreign host"
This error indicates that the inetd process is recognizing the incoming connection (/etc/services is correct) but there is an error in your /etc/inetd.conf file, possibly a path error. 
 "Connection refused"
This error indicates that /etc/services is not correctly set up, be sure the port it is using is 5109. If you are using term, and this error appears when telnetting to your remote term host, it's likely that it's a tredir error.

Things to check: /etc/services entry /etc/inetd.conf entry, paths, and you have reset inetd (kill -1 ) tredir is running correctly.

Q: I do not seem to be logging voice mail?

A: Be sure you have a /tmp/vmail directory, this is where voice mail is logged (subject to change).

Q: How do I initiate Voice Mail logging? (and shut it off)

A: The ztalk and xztalk clients both do this within the client, but if you with to do it manually, you need only create or remove a file called '/tmp/.ztalk_away' which the ztalkd daemon uses to determine your Voice Mail status.

To turn off voice mail logging: 

      % rm /tmp/.ztalk_away
To turn on voice mail logging: 
 
      % touch /tmp/.ztalk_away
Q: How do I play voice mail messages?

A: The easiest way is to cat them to the /dev/audio device: 

     % cat /tmp/vmail/* > /dev/audio
There is a utility called 'vmplay' that also plays voicemail messages. Xztalk has built in Voice Mail message handling, deleting, playback and forwarding.
Liem Bahneman roland@cac.washington.edu