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3. Features

3.1 feature_not: Which ISDN features cannot be offered by isdn4linux?

Some ISDN features are device-specific and cannot be activated by isdn4linux for other devices, unless isdn4linux were to falsify the TEI (which would probably confuse the other device). Such device-specific ISDN features are, among others: rejection of a waiting call, caller id on/off, hold, conference calls, differing COLP/CLRP.

3.2 feature_data: Which ISDN data transmission modes are supported?

These low-level formats are possible:

These level2 formats are possible: These encapsulations are possible:

Please note that X.31a is supported as X.25 on top of ISDN, while X.31b is not supported (neither in the B channel, nor in the D channel variation).

3.3 feature_voice: Has isdn4linux voice support (e.g. answering machine, voice-over-ip gateway for H.323 clients)?

Yes, voice support is included in the current version of isdn4linux. For an answering machine you can either use "vgetty" from Gert Doerings "mgetty+sendfax", or "vboxgetty" from Michael Herold, which is made especially for isdn4linux. The latter is part of the isdn4k-utils package, which can be found on: ftp://ftp.isdn4linux.de/pub/

Also, you can use isdn4linux as a voice-over-ip gateway to let H.323 clients (like Voxilla, Netmeeting) call normal telephones, and/or the other way around. For configuration see question config_h323.

3.4 feature_fax: Can I fax with isdn4linux?

If you do want to fax now, your best choice is to install an analog fax modem along with your ISDN card. For companies who want to set up a fax server servicing multiple connections you could also have a look at the active ISDN cards.

3.5 feature_modem: Can isdn4linux connect to/be called by an analog modem?

Generally: NO. It may only work for cards with which you can fax: see question feature_fax.

3.6 feature_divert: Is it possible to initiate call forwarding with i4l?

Call diversion features have been implemented recently. Use the new program divertctrl. So far there is no howto and only little documentation, so for now this is something only for the more experienced user. In the Netherlands, the keypad protocol can be used as an alternative.

3.7 feature_ipx: Can I route ipx/spx over ISDN with Linux?

Yes, just set up an ISDN interface with encapsulation ethernet. mars_nwe can do the rest (e.g. routing). Also, you can route ipx with ipppd, see question syncppp_ipx. To use pppd for ipx, you have to give it the compile option IPX_CHANGE.

3.8 feature_2channel: Does isdn4linux support channel bundling?

The current version of isdn4linux support 2 methods of channel bundling:

Both variants have their own advantages and disadvantages. See section 2channel. Bonding (16bit channel) is not supported, since it can not work reliably when the dialup connections have deviating latency. Warning: Channel bundling saves time, but not telephone charges. It is useful only if you really need the extra bandwidth.

3.9 feature_diald: Can I combine isdn4linux with diald?

Yes, you can. You have to configure it to use the ttyI* devices to dial out. E.g. like this:


/usr/sbin/diald /dev/ttyI4 -m ppp [...]

where [...] stands for further dialout parameters.

3.10 feature_dod: Does the driver support "dial on demand"?

Yes. If a network interface (e.g. "isdn0") is set up, the driver will dial the number. If in addition a hangup timeout (Idle Timeout) has been given (like: isdnctrl huptime <interface> <time>), then the driver will automatically hang up when no data was been transferred over the interface for >time< seconds. However, with syncPPP there are problems (see the syncPPP section). Also look at the dialmode description (see question dialout_dialmode). You should definitely be very interested in the large section of this FAQ that talks about the dangers of unwanted dialouts: ( dod).

3.11 feature_sms: Can I send SMS (short messages) to my mobile phone via ISDN?

Yes, you can use the program yaps to do this. However, due to some pecularities in the SMS-callcenter's ISDN connection, you have to compile the kernel with the options Disable send complete and Disable sending llc.

3.12 feature_btx: Is the German videotex/Btx/Datex-J possible with isdn4linux?

Yes, it works with the modem emulation with the ttyI* devices. There is a special register to set for videotex (ATSx=y - see the Readme's) Warning! XCept (formerly Xbtx) has an ISDN configuration option. This should NOT be used. XCept should be configured as if a normal modem were being used.

3.13 feature_clock: How can I set the clock of my computer with ISDN?

Isdnlog offers this feature with option "-t". Unfortunately, the seconds are not transmitted via ISDN, and the transmitted time is not very accurate - depending on the ISDN equipment of your telephone company there may be a deviation of several minutes (!). It's better to get a PC clock that is set by radio signals and check it with, for example, xntp. You can also use a time server in the Internet with "netdate" or "rdate". One time server can be found in Cologne: time.rrz.uni-koeln.de, but there are many more.

3.14 feature_dosemu: Can I use isdn4linux under dosemu?

Yes, you can! Steffan Henke henker@informatik.uni-bremen.de wrote on 25 Oct 96:

In dosemu.conf it is enough to enter a virtual com port, (for example com2) that can be used with e.g. Telix or Terminate: serial { com 2 device /dev/ttyI3 } Access with Fossil is possible if fossil.com (included with dosemu) is started. Tested with the following configurations: - Kernel 2.0.21, Teles driver incl. Karsten's patches - Kernel 2.0.21, HiSax

3.15 feature_capi: Is there a CAPI interface available?

Currently, these cards support the CAPI 2.0 interface:

This interface follows the official CAPI 2.0 standard that was established recently for Linux by the CAPI Association (see http://www.capi.org). There are activities to make this a general interface, also for other cards. However, there are no plans to implement a CAPI 1.1 interface.

3.16 feature_uus: Is UUS (user to user signaling) supported?

Yes, isdn4linux could support both sending and receiving, but the implementation is currently rather incomplete due to the unclear legal situation for using this facility. Receiving UUS is only possible through the debug interfaces. Sending is supported in connection with the diversion services (when rejecting a call or announcing a busy condition), but not on an ordinary call. It is recommended to use subaddressing (see question feature_subaddressing) instead. Please note that sending UUS it is not a free service (receiving is free), at least with some German phone providers you have to pay extra for it (also have a close look on the usage conditions). Additionally, please note that if you are connected through a PBX, it may filter out all the UUS stuff.

3.17 feature_subaddressing: Is subaddressing supported?

Yes, isdn4linux does support subaddressing (available in France). To configure it, give HiSax the number in this format: <number>.<subaddress>. However, you may have to order it seperately and pay extra for receiving it (sending is free), depeding on your ISDN provider. Additionally, please note that if you are connected through a PBX, it will most likely filter out all the subaddressing stuff.

3.18 feature_gsmv110: Can I connect from my PDA via GMS cellular phone to isdn4linux?

Yes, if the provider of the cellular phone has a GSM to ISDN/V.110 gateway. This has been reported to work from a PalmPilot to isdn4linux with V.110. See question config_gsmv110 for details on how to configure it.

3.19 feature_lcr: Can isdn4linux do least cost routing (LCR)?

Yes, this feature is now being supported by isdnlog. What it does is that it allows isdnlog to choose your telephone provider when placing a call through your ISDN card, depending on the time of day and the current rate information. Please note, that it does not make much sense to choose a call-by-call Internet Provider this way, since more things would have to be adjusted to make it work (e.g. DNS lookup, proxy setup,...). Also, isdnlog should always be running (otherwise your dialout may be delayed by 3 seconds).

3.20 feature_future: Which features are planned for the future?

Actually, most features have been implemented and are now being improved. But, who knows what other interesting stuff the developers may come up. We'll see...


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