<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML> <HEAD> <META NAME="GENERATOR" CONTENT="LinuxDoc-Tools 0.9.21"> <TITLE>FAQ for isdn4linux: glossary: ISDN specific words which are used in this FAQ </TITLE> <LINK HREF="i4lfaq-28.html" REL=previous> <LINK HREF="i4lfaq.html#toc29" REL=contents> </HEAD> <BODY> Next <A HREF="i4lfaq-28.html">Previous</A> <A HREF="i4lfaq.html#toc29">Contents</A> <HR> <H2><A NAME="glossary"></A> <A NAME="s29">29.</A> <A HREF="i4lfaq.html#toc29">glossary: ISDN specific words which are used in this FAQ </A></H2> <P> <DL> <DT><B>active card</B><DD><P> <A NAME="glossary_active"></A> Cards can come in different versions: passive, semi-active, active. Active cards handle the D-channel and B-channel protocol in their hardware. The extra hardware makes them more expensive, but better suited to use where a low CPU usage is needed (e.g. when having many ISDN cards in one computer). Because of their special hardware, a special driver is required. Depending on the hardware/driver, special tasks like sending/receiving analog G3 faxes may be very easy to implement - if you need these features, get one of them.</P> <DT><B>AOC-D</B><DD><P>"Advice Of Charge During the Call".</P> <DT><B>AOC-E</B><DD><P>"Advice of Charge at the End of the Call". In Germany, this service is included in the "Komfort" connection.</P> <DT><B>BRI</B><DD><P>BRI means basic rate interface and is the most commonly used interface. In Europe, a BRI includes 2 B-channels for data communication, and 1 D-channel for administration of the data communication. The alternative is a PRI interface.</P> <DT><B>CLIP</B><DD><P>CLIP (Calling Line Identification Presentation) can be offered by the ISDN provider. When you call somebody, then your telephone number will be transmitted to the other phone. The opposite of CLIP is CLIR. In Germany, CLIP is the default.</P> <DT><B>CLIR</B><DD><P>CLIR (Calling Line Identification Restriction) can be offered by the ISDN provider: one can (from call to call) restrict the identification of one's own caller ID to the other party. The opposite of CLIR is CLIP. In Germany, this must be applied for but is without charge (however call by call transmission of the caller ID costs extra).</P> <DT><B>COLP</B><DD><P>COLP (Connected Line Identification Presentation) can also be offered by the ISDN provider. If you've applied for COLP, you get an extended dialing protocol. You will receive feedback from your telecommunication company who picked up your outgoing call. Normally, you will get the same number as you dialed beforehand; however, with call diversion this could also be a different number. In Germany, it must be applied for, and costs extra. More information than COLP can be obtained with the help of a reverse-connected ISDN card.</P> <DT><B>CVS Tree</B><DD><P>The i4l developers have formed a team. The tool CVS allows the members to easily make patches. The history of the project is also thereby documented, and it is also not difficult to reproduce older versions.</P> <DT><B>EAZ</B><DD><P>This is a German name for an MSN. In Germany, EAZ and MSN are used as synonyms, though in theory one ought to differentiate according to the protocol used. That which is called MSN in the Euro-ISDN protocol was called EAZ in the German 1TR6-ISDN protocol (a German predecessor to Euro-ISDN).</P> <DT><B>HDLC</B><DD><P>A widely used low-level protocol, usually used to connect your computer with your internet provider. To connect to a computer mailbox, usually X.75 is being used.</P> <DT><B>HSCX</B><DD><P>A Siemens chip which is, similar to ISAC, on many passive cards. It takes over the serial bus from ISAC and demultiplexes when receiving or multiplexes (i.e. inserts the bits in the correct position) the B channels.</P> <DT><B>ISAC</B><DD><P>A Siemens chip which is, similar to HSCX, on many passive cards. It is responsible for Level 1, so it sits (almost) directly on the line. It handles the D channel protocol and sends the S0 data to a special serial bus (IOM). When sending it does the opposite.</P> <DT><B>leased line</B><DD><P> <A NAME="glossary_leased"></A> Your telecommunication company can hardwire the connection between two of their ISDN users. Then these users are always connected to each other without dialing and can not dial out to someone else any more.</P> <DT><B>MSN</B><DD><P>Unlike a normal telephone connection, an ISDN connection can have more than one telephone number - each of these is called an MSN (Multiple Subscriber Number).</P> <DT><B>NT</B><DD><P>NT is the abbreviation of network terminator. This is the interface between an ISDN user and the ISDN provider. It is a small hardware box to which the user has to connect his ISDN devices via a so called S0 interface. In most European countries, the ISDN provider supplies the NT. A user in North America usually has to buy one, therefore the NT is often integrated into the ISDN card there.</P> <DT><B>NT mode</B><DD><P> <A NAME="glossary_ntmode"></A> When multiple devices are connected to the ISDN connection, then all user device behave as slaves, where the network terminator (NT) behaves as master and synchronizes the communication on the S0 bus. The special behavior of the network terminator is called NT mode. User devices are normally not capable of running in NT mode. As a result, user devices can not communicate with each other even when they are connected via a crossed cable. Only some special ISDN cards (HFC chipset) are capable of running in NT mode, and can directly communicate with other ISDN user devices via a crossed cable.</P> <DT><B>multi-device mode</B><DD><P> <A NAME="glossary_multidevicemode"></A> Your ISDN interface can be configured either in multi-device mode (in German: Mehrgeraeteanschluss), or in point-to-point mode (in German: Anlagenanschluss). The multi-device mode is the normal connection mode for private ISDN users or very small business users. The user can attach multiple devices to the ISDN connection. The ISDN provider will assign a small number of fixed telephone numbers (usually up to 10 MSN), if any, to the ISDN connection.</P> <DT><B>passive card</B><DD><P> <A NAME="glossary_passive"></A> Cards can come in different versions: passive, semi-active, active. Passive cards handle the D-channel and B-channel protocol in software. This makes them least expensive, but only suitable where the CPU is able to do the additional work (for normal data communication any computer starting from a 486 or even a 386 should be able to handle one or two cards). Since only a few hardware chips are in wide usage, a generic driver, HiSax, can handle almost all passive cards.</P> <DT><B>PBX</B><DD><P>A PBX (Private Branch eXchange) is used to connect different internal devices to the ISDN network. This is usually for analog devices that cannot be directly connected to an ISDN network. The PBX can also make an internal digital S0 bus available, on which ISDN devices can be connected. This allows for local calls without using the switching station (thereby avoiding the charges from your telephone company).</P> <DT><B>point-to-point mode</B><DD><P> <A NAME="glossary_pointtopointmode"></A> Your ISDN interface can be configured either in multi-device mode (in German: Mehrgeraeteanschluss), or in point-to-point mode (in German: Anlagenanschluss). The point-to-point mode is the normal connection mode for business ISDN users. The user can attach only one single devices to the ISDN connection which will have to handle all calls (typically a PBX will be used). The ISDN provider will assign a range of numbers to the ISDN connection. Any call within this number range will be sent to the user. The ISDN provider will leave assignment of the last digits of the telephone number to the ISDN user. This setup usually allows for additional features, but is also more expensive.</P> <DT><B>PRI</B><DD><P>PRI means primary rate interface and is the used when a single or multiple BRI are not sufficient in bandwidth. In Europe, a PRI includes 30 B-channels for data communication, and 1 D-channel for administration of the data communication.</P> <DT><B>semi-active card</B><DD><P> <A NAME="glossary_semiactive"></A> Cards can come in different versions: passive, semi-active, active. For semi-active cards there is no fixed definition, so here is what we think: semi-active cards handle the B-channel protocol in their hardware with special DSP (digital signal processor) support, but they leave the D-channel protocol to the software. This makes them better suitable to special tasks like sending/receiving analog G3 faxes. Because of their special hardware, a special driver is required. Be aware, that for marketing reasons some cards are called semi-active when in fact they are passive (e.g.: Teleint).</P> <DT><B>subaddressing</B><DD><P>When dialing, it is possible to provide an additional number, the subaddresss. The subaddress is transmitted to the remote side, and allows it to react on it. This feature may not be available, at least not for free (with the exception of France).</P> <DT><B>TEI</B><DD><P>TEI stands for Terminal End Identifier. The local switching station, or with an internal S0 the PBX, automatically or permanently assigns each end device a TEI. This simply allows the addressing of the D channels. TEIs have the following values: 0-63 = permanent TEIs (e.g. 0 is used for point to point connections) 64-126 = automatically assigned 127 = broadcast to all devices (e.g. an incoming call)</P> <DT><B>UUS</B><DD><P>UUS is user to user signalling. It means, that when placing a call, a few bytes of user-specific data can be transmitted along with the call setup frame. This feature has been abused in the past in Germany, causing the local exchanges to run out of available channels (the call setup causes them to reserve a B-channel). Since then, this feature usually costs extra and there is a data limit on it (depends on your ISDN provider). Have a look at the usage condition, in short it's only allowed to use this feature, if indeed you want to setup a call. Please note that it has been reported that some buggy PBX (like ISTEC 1003) may refuse a connection when support of UUS is signalled to them.</P> <DT><B>X.75</B><DD><P>A widely used low-level protocol, usually used to connect your computer with a computer mailbox. For connections to the internet, HDLC is usually used.</P> </DL> </P> <HR> Next <A HREF="i4lfaq-28.html">Previous</A> <A HREF="i4lfaq.html#toc29">Contents</A> </BODY> </HTML>
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