The

User's Manual

Release 0.8.0, (C) 1999

The kISDN telephone

kISDN's (v0.7) most thrilling feature is its built in telephone. It is the first - at least as far as we know - that you can make telephone calls with your Linux computer using a GUI program. This new feature is quite demanding when it comes to hard and software requirements, you will read more about it in the next chapter. We are planning on separating the telephone from kisdn in the same way it happened to kcmkisdn. kISDN will then be a package or individual components, which will all rely on one configuration.

16. Preparations

Before you can enjoy a tool that was previously exclusively available to users of alternative operating systems (you probably know what I mean), you will have to do some extra preparations. The central keyword to telephony is fullduplex; what does that mean? A telephone conversation is (usually) a dialogue, meaning that the communication is bidirectional: I can hear him(her) and he(she) can hear me. The other party can hear me, because my voice is translated into electric impulses by the microphone, which are again turned into digital format by my soundcard, from where it will then be send to the other party over the ISDN connection. This is also why I can hear the other side: I receive digital information from the ISDN connection, which are in turn turned into analog data and made audible through my speakers/stereo. To be able to hear and speak at the same time, both soundcard and driver must be able to transport audio data in two directions. Cards and drivers that can only transport audio in one direction at a time are called halfduplex devices, those capable of operating in two directions are called fullduplex devices.
Obviously it makes little sense to use halfduplex hard and/or software for telephony, thus you must find out about your hard/softwares capabilities.


Hardware (Soundcards)

Unfortunately we have very little information about fullduplex capabilities of the different soundcards available. On thing we can say for sure, though: The Soundblaster 16 and all of its successors (AWE32/AWE64/AWE64Gold) are fullduplex devices.


Software (drivers)

The most common problem arises from the standard Linux sound driver (OSS/Free) which is not fullduplex capable :-( There are said to be patches which add fullduplex capability, but you will probably be happier with one of the following alternatives:

  • The commercial version of OSS/Linux (Open Sound System, current version 3.9.1g), available against a fee of $20. Get it at 4Front-Tech
  • The ALSA-Treiber (Advanced Linux Sound Architecture), wich is currently under development and licensed under the terms of the GPL (free); it is available at http://alsa.jcu.cz
We tested kISDN with both drivers and found both to be good, but the installation of the ALSA driver turned out to be slightly more complicated than that of the OSS/Linux drivers.

If you successfuly installed your new drivers, you can easily verify their fullduplex capability by typing:

cat /dev/sndstat

You will find usually find a hint at it:

Audio devices:
0: SoundBlaster PnP (4.16) (DUPLEX)
1: SB secondary device (DUPLEX)

You should also test if other sound applications work correctly with the driver to disclude potential error sources.


17. Starting it up

Please start the dialer (kisdn) and open the main window (if kisdn was docked). Have a look at the two LEDs below the telephone button:

Telefon-Button

If the green LED is lit (like in the image above), your audio system is set up correctly - if the red one is lit, there is an error somewhere; kISDN usually displays a message box describing the problem on startup.
As long as the red LED is lit, kISDN telephony is disabled. The monitoring of incoming calls still works, but you cannot accept them.

If the green LED is lit you are most likely ready to go :-).


18. The first call

Please open the telephone dialogue by pressing the button mentioned above; you should now see the following window:

Telefon-Dialog 1

Enter the MSN of your regular phone; this can be done either with the mouse or with the keyboard. Go ahead and click the 'Dial' button,

Wählen-Button

(don't forget to activate both speakers and microphone) and go to your phone: it rings. Calling yourself is usually quite difficult, so go ahead and press the 'Hangup' button.

Auflegen-Button

Your phone should mute. Press space to clear the number in the display and enter the number of some info service or that of a (good) friend (you can never know what happens to kISDN on your first call, thus it's probably not a good idea to call your boss ;-). Again, all you have to do the 'Dial' button; you should not have any problems, but who knows ...


19. The different telephone controls

Have a look at the telephones different items. This is the telephone display, for example:

Telefon-Display

The upper line shows the other party's phone number, below you will either see a name, if kISDN knows the number (it must be entered in the phonebook) or 'unknown'. The third line shows the ISDN line's status, in the case above it's 'Idle', meaning that we are neither connected nor are we being called.

Possible values are:

Idle
The line is not being used (neither incoming nor outgoing).
Incoming call
A call is coming in; You can accept it by pressing the 'Dial' button.
Outgoing call
You have entered a number and pressed the 'Dial' button, a connection has not yet been established (the other party did not answer yet)
Connected (on)/(off)
We are connected; '(on)' or '(off)' indicate whether we have to pay for the connection.
Mute (on)/(off)
Indicates if the connection was set to 'mute'; Caution: '(on)' and '(off)' concern the state of the muting function!
Failure (off)
You tried to make a call, but a connection could not be made (e.g. you tried to call your own MSN).
Hungup (We)/(He)
Will be displayed for a couple of seconds after a connection was terminated, '(We)' indicated that we hung up, '(He)' on the other hand tells up that the phone was hung up on us ;-(.

To the right of the line state indicator is a small clock that tells us something about the call's duration (which can be very helpful !).
Below the display you can see different buttons that do the following
:
The currently displayed number is called, if no number is displayed and a call comes in, you can accept it using this button.
The connection is terminated or a dial attempt is canceled.
Turns the answering machine on or off (new in kISDN 0.8).
Opens the phonebook that you can use to choose a number you want to call.
Opens the caller's list; all incoming calls are listed with date and time.

The telephone 'keyboard' also contains some function keys:

Deletes the rightmost digit on the display - equivalent to pressing the [BackSpace] key on your keyboard.
Deletest the entire number currently displayed - equivalent to pressing [Space] on your keyboard.
Call repitition. The number that was called last is shown on the display; a click on the 'Dial' button redials that number.
Muting. Pressing this button will mute the connection in both directions, the display will show 'Mute'. Repressing the button will exit muting mode, the display will show 'Connected'.

There's a little built in gimmick: If you enter the first digits of a phonenumber and kISDN can find an exact match, it can be completed by pressing the [<] key.

Quit often, you will notice during a connection, that the other party can barely be heard; likewise, he(she) might complain that you are too loud. Since you speak freely, this can be hardly avoided. Also, if your speakers are set too loud, the other party might hear itself (or - in the worst case - a terrible whisle - acustic feedback). kISDN allows setting your microphones sensitivity and the speakers volume to remove the need for a mixer:

Audio-Panel


Moving the slider all the way to the left mutes the speakers/microphone, moving it all the way to the right sets it/them to maximum. The use of headsets greatly reduces the problems mentioned above, but high quality headsets are rather expensive.

Last but not least there's the recorder, which is not yet implemented in version 0.7. It will allow recording entire conversations or parts; we have extensive plans, when the future of kISDN is concerned (caller-sensitive answering machine, least cost routing, videotelephone etc...).


20. Treatment of incoming calls

Depending on the dialogues open and their state, incoming calls are handeled differently.

  • If the phone dialogue is closed or kISDN docked, a small message box pops up:

    Anruf-Signalisierung

    Now you may either ignore the call (Caution: you won't be able to change your mind, even though the call is still waiting, as can be noticed by a lit yellow LED!) or accept it. Given the latter case, the phone dialogue is opened and caller, line state and duration are displayed.

  • If the phone dialogue is open and you were just entering a number (the phonenumber display is not empty), again a message box pops up (if it didn't, all digits entered so far would be deleted, no matter if you want to answer the incoming call or not). The rest of the process is as previously described.
  • If the phone dialogue is open, but the display is still empty (you did not start entering a phone number), then kISDN prints all information directly into the display. You may then accept the call by pressing the 'Dial' button.

Back to the overview


T. Westheider, Ch. Zander / January 8 1999 - kISDN Release 0.8.0