name mode size
ann_b2b 040000
announce_transfer 040000
announcement 040000
conf_auth 040000
conference 040000
early_announce 040000
examples 040000
ivr 040000
mailbox 040000
mp3 040000
pin_collect 040000
py_sems 040000
reg_agent 040000
registrar_client 040000
voicemail 040000
webconference 040000
Makefile 100644 1.15kB
+------------------------------------+ | SIP express media server - README | +------------------------------------+ Introduction: SEMS is a free, high performance, extensible media server for SIP (RFC3261) based VoIP services. It is intended to complement proxy/registrar servers in VoIP networks for all applications where server- side processing of audio is required, for example away or pre-call announcements, voicemail, or network side conferencing. SEMS can be used to implement simple high performance components like announcement servers as building blocks of more complex applications, or, using its powerful framework for application development including back-to-back user agent (B2BUA) functionality, complex VoIP services can be realized completely in SEMS. The following applications are shipped with SEMS : * announcement: plays an announcement * voicemail: records voice messages and sends them as email * conference: enables many people to talk together at the same time * webconference: conference application that can be controlled from an external program, e.g. a website * echo: test module to echo the caller's voice * mailbox: auto-attendant that saves voicemails into an IMAP server. Users can dial in to check their messages * ann_b2b: pre-call-announcement, plays announcement before connecting the callee in B2BUA mode * announce_transfer: pre-call-announcement, plays announcement and then transfers the caller to the callee using REFER * early_announce: (pre-call) announcement using early media (183) * conf_auth: collect a PIN number, verify it against an XMLRPC authentication server and connects in B2BUA mode * pin_collect: collect a PIN, optionally verify it, and transfer the call into a conference alongside a set of example applications intended to help development of custom services, including a calling card application, a traffic generator, a component to control the media server via XMLRPC, and announcements played from DB. SEMS' core implements basic call and audio processing, and loads plug-ins which extend the system. Audio plug-ins enable new codecs and file formats, application plug-ins implement the services' logic. Other modules called component modules provide functionality for other modules to use. You can easily extend SEMS by creating your own plug-ins. Applications can be written using the SEMS framework API in C++, or in Python using an embedded python interpreter of the ivr or py_sems modules. SEMS only supports patent free codecs. That means that codecs like g729 won't be supported. On the other hand, SEMS supports all important patent free codecs out of the box (g711u, g711a, GSM06.10 and iLBC). Integrating other codecs in SEMS is very simple. SEMS shows very good performance on current standard PC architecture based server systems. It has sucessfully been run with 1200 G.711 conference channels on a quad-core Intel(R) Xeon at 2GHz (700 GSM, 280 iLBC channels). On the other hand it also runs on very small devices - for example small embedded systems like routers running OpenWRT, for which of course the achievable channel count is not that high. Requirements: 1. SER version 0.9.6-sems: SIP Epress Router ( SEMS uses SER as its SIP stack. SEMS & SER communicate through unix socket, which means that a SER instance is mandatory on every host using SEMS. 2. Python version >= 2.3 for the ivr (embedded python interpreter) and py_sems, optional 3. flite speech synthesizer for TTS in the ivr, optional 4. lame >= 3.95 for mp3 file output, optional How to get started with SEMS: To try out SEMS, the easiest is to get the bundle and install it: wget tar xzvf sems-0.10.0-bundle.tar.gz ; cd sems-0.10.0-bundle make install PREFIX=~/sems-0.10.0-install SERPREFIX=~/sems-0.10.0-install This gets you the default set of applications installed in that directory, and in the end prints the commands to start it. You can also follow one of the tutorials linked from the SEMS homepage (e.g. Application Modules Documentation page then gives an overview of the application modules that come with SEMS ( If you are interested in writing your own applications, the application development tutorial is a good start (, together with the design overview ( and the example applications (apps/examples/). Installation: 1. Download SEMS Download the source tarball from, or get the newest version through svn: $ svn checkout svn:// -or- $ svn checkout 2. Compile SEMS $ make all $ make install Notice: you don't need to execute 'make install' if you want to run SEMS from the source tree, but in this case some paths in the config files will need to be adapted. If you want to install to a different prefix than /usr/local, use PREFIX=/some/other/prefix For detailed instructions for some modules, have a look at doc/COMPILING as well. 3. Look at the default configuration file whether it fits your need: If you installed SEMS with 'make install', the configuration is at '/usr/local/etc/sems/sems.conf'. Else make your own using sems.conf.sample. 4. Get and start SER as SIP stack for SEMS: To install the ser-0.9.6-sems into the directory /some/dir the following commands can used: $ wget $ tar xzvf ser-0.9.6-sems_src.tar.gz $ cd ser-0.9.6-sems $ make install PREFIX=/some/dir With the install target install-ser-cfg, e.g. using $ make install-ser-cfg SERPREFIX=/some/dir you can install a general ser-sems.cfg which will work with ser-0.9.6-sems and make SER to act only as SIP stack for SEMS, i.e. direct every request to SEMS. Then $ /some/dir/sbin/ser -f /some/dir/etc/ser/ser-sems.cfg runs SER on port 5070. This way, several versions of SER can be used on the same server, e.g. a different version of SER as Registrar server. 5. Start SEMS: If you installed SEMS with 'make install', sems can be found at '/usr/local/sbin/sems'. If you need help starting 'sems', try 'sems -h'. 6. Using SEMS SEMS needs to be told from the many possible applications that are loaded which one to run. You can simply set default_application in sems.conf. Another method is to append a header P-App-Name: <app name> to the INVITE, for example P-App-Name: conference or P-App-Name: echo In a typical SER-setup where an incoming INVITE should be sent off to conference, the following lines can be executed in the proxy's (!) ser.cfg (assuming the media server runs on the same host with its SIP stack SER on port 5070): append_hf("P-App-Name: conference\r\n"); t_relay_to_udp("","5070"); break; A sample ser.cfg with which many applications can be tried is available at Alternatively, the SIP-stack-SER can be configured in ser-sems.cfg to send all calls directly to one application, in that case the line if(!t_write_unix("/tmp/sems_sock","sems/app_headers")) in ser-sems.cfg could be changed to e.g. if(!t_write_unix("/tmp/sems_sock","conference")) A sample ser.cfg file in this style can be found at For more information please refer to doc/Configure-SEMS-Ser-HOWTO and the SER User's guide. Installed files using 'make install': /usr/local/sbin/sems : SEMS executable /usr/local/lib/sems/plug-in/* : plug-ins /usr/local/lib/sems/audio/* : default path for audio files /usr/local/lib/sems/ivr/* : precompiled IVR scripts /usr/local/etc/sems/sems.conf : configuration file /usr/local/etc/sems/etc/* : modules configuration files /usr/local/share/doc/sems/README : this README. source_path/scripts/sems[.redhat] : example start-up scripts. source_path/sems.conf.example : example configuration file. Documentation: In the doc/ directory there is a set of files describing the applications shipped with SEMS, alongside some more documentation. Generate the doxygen documentation with 'make doc' in doc/doxygen_doc, that contains all these files as well. All this and more documentation is available online linked from the SEMS homepage: Support, mailing lists, bugs and contact: Please have a look at the documentation and other information on the SEMS homepage ( Best-effort support is given through the mailing lists for SEMS, and, which are the first address to ask for help, report bugs and improvements. You need to be subscribed to be able to post to the lists: The mailing list archives at and can be a great help as well (especially with google site search on, e.g. ). The bug tracker for SEMS is at Please submit all bugs, crashes and feature requests you encounter. Authors: Raphael Coeffic (, the father of SEMS, Stefan Sayer (, current lead developer, and all contributors. Contributions: All kinds of contributions and bug fixes are very welcome, for example new application or codec modules, documentation pages, howtos etc. Please email one of the lists or the authors. Special thanks goes to: * Juha Heinanen for numerous bug reports, improvements and contributions * Ulrich Abend ( for his great debuging work and ISDN gateway which unfortunately did not make it into this version yet. * Jiri Kuthan ( for the debuging work and help to implement the first communicating part between Ser & SEMS ('vm' module). * iptego GmbH and iptelorg for sponsoring development and improvement of SEMS. * All the others who helped during test session and reported bugs :-) SEMS - the media-S in the SLAMP.