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1 README version 22jun2005
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2
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3 Welcome to intercom, a Voice over IP speaker-phone conference
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4 application. The application can:
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5 - dial a intercom partner via short-dial buttons
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6 - make a RTP connection to transport your voice over IPv4
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7 - make a telephone conference
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8 - support wideband codec (16kHz sample frequency)
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9
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10 Intercom is still very limited. But the things it can do, it does
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11 very well!
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12
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13
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14 Modify file ~/.intercom.conf for your short-dial labels
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15 and your IP-addresses.
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16
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17 To start the application enter
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18
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19 intercom
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20
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21 Read shell script /usr/local/bin/intercom to get an idea of what is
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22 going on. For better echo cancellation start intercom with the -m or
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23 -l option.
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24
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25 For a first test talk to yourself by clicking the button for your own
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26 IP-address, e.g. EDDF TEC2 if your computer is 192.168.1.2.
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27 The button should become green.
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28 Attention: A short click (less then 300ms) toggles on/off, a long
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29 click works as push-to-talk.
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30
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31 ATTENTION: The intercom application needs PCM out for playback. This
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32 hardware device is used also by other sound programs like MP3 players
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33 (e.g. xmms) or WAV record/playback programs like sweep and audacity. The
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34 intercom application blocks (freezes) as long as another program uses
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35 PCM out. There are ways around this like using sound daemons aRTs or
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36 esound. But this is outside of the intercom application.
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37
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38 If you dial another intercom station, you get an one-way connection from
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39 your microphone to the loudspeaker of your intercom partner. If your
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40 partner clicks on the correct button (the magenta one), both of you have
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41 a two-way communication. Now you or your partner can dial more intercom
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42 stations to make a conference with maximum 6 stations.
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43 Note: Start intercom with the -t option to get "everybody can talk and
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44 listen with everybody else".
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45
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46
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47 Read the file
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48 http://home.arcor.de/andreadrian/intercom/draft-conference-01.txt
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49 for more information.
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50
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51
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52 Supported royalty free Codecs:
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53 For License see ITU-T G.191 or IETF RFC3951
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54
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55 Narrowband (8kHz sample frequency):
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56 -----------------------------------
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57 IETF iLBC 15.2kBit/s Global IP Sound iLBC Public License
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58 ITU-T G.711 A-law 64kBit/s ITU-T SOFTWARE TOOLS' GENERAL PUBLIC LICENSE
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59 ITU-T G.711 u-law 64kBit/s ITU-T SOFTWARE TOOLS' GENERAL PUBLIC LICENSE
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60 ITU-T G.726 32kbs 32kBit/s ITU-T SOFTWARE TOOLS' GENERAL PUBLIC LICENSE
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61 3GPP GSM 13.2kBit/s ITU-T SOFTWARE TOOLS' GENERAL PUBLIC LICENSE
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62
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63 Wideband (16kHz sample frequency):
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64 ----------------------------------
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65 Speex 27.8kBit/s Xiph.org license (BSD license variant)
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66
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67 Author: Andre Adrian
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68 E-Mail: Andre dot Adrian at dfs dot de
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69 Postal: DFS Tower Frankfurt
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70 Mr. Andre Adrian
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71 Flughafen Gebaeude 501
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72 60549 Frankfurt, Germany
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