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5. hardware: Supported hardware, its specialities, and hardware-related problems

5.1 hardware_support: Which hardware is supported?

Only internal cards that plug into an ISA or PCI slot are supported. ISA Plug&Play cards are also supported, but need some additional manual configuration by means of the isapnptools. For details on the configuration see question config_pnp.

Internal cards may be active, semi-active, or passive. Unless you have paid big money, assume you have a passive card. More about the difference: see question hardware_activepassive.

Right now there is a driver for all passive card with certain Siemens chipsets (HiSax driver). Have a look at the README.HiSax that comes with the driver for the most up to date information on supported cards. Here the status from 4th September 1999 (constantly improving):

Note:

The following cards are definitly not supported and will probably never, since the producer does not give out the specifications for their very proprietary hardware/protocol:

5.2 hardware_activepassive: What is the difference between an active and a passive ISDN card?

An active ISDN card handles most of the ISDN connection protocols (dialing, accepting calls, etc.) itself. The card includes a kind of minicomputer with its own software (firmware). With a passive card, the computer in which the card is installed has to perform these functions.

In principle, both types are supported by isdn4linux. However, since active cards have non-standard interfaces, a driver can only be made when the producer publishes the interface. Also, the card's firmware needs to be made freely available. In contrast, many passive cards share the same chipset. Therefore many passive cards can be supported once a driver supports this one chipset.

These active cards are currently supported by an individual driver:

5.3 hardware_recommend: Which card is recommended by the developers?

The developers suggest to use ELSA cards. ELSA has made their specifications available to the developers, and provided a lot of support, resulting in an excellent driver. Also, their cards are certified for usage in Germany, see question country_certified.

5.4 hardware_external: Does isdn4linux support external terminal adapters?

No, but it doesn't need to. Terminal adapters are designed to behave either like a modem or like a network card. Linux already supports both modems and network cards without isdn4linux - so no special ISDN driver is necessary (which usually greatly simplifies the configuration).

5.5 hardware_irq: Why should I avoid IRQ 12 and 15 for my ISDN card?

On many PCI boards, interrupt 12 is often used by a PS/2 mouse (even though you may not have any or the IRQ is not activated for it). It may be used even when you have no PS/2 port. Interrupt 15 is also often used by the second IDE bus (even when you are not using it or the IRQ is not activated for it). Even though one thinks that some IRQs are available they are still somehow reserved by the BIOS. Good IRQs to try are always IRQ 5 and IRQ 9. Without mice or modems you could also try 4 and 3, which works even on very exotic boards.

5.6 hardware_s2m: Which S2M cards are supported?

At least these S2M cards have been reported to work:

5.7 hardware_smp: Can I run isdn4linux on my multi-CPU board?

Yes, this works nicely. However, make sure to compile the kernel and all modules with option SMP. If you run into problems when both CPUs try to handle the same IRQ, try to boot with noapic.

5.8 hardware_alpha: Can I run isdn4linux on a DEC Alpha with Linux?

Yes, most cards should run with isdn4linux on a DEC Alpha. Many cards have been reported to work with the HiSax driver. Also the active ICN card has been reported to work.

5.9 hardware_maxcards: How many ISDN cards can I put into my computer?

It depends on the availability of slots, interrupts/IO addresses in your computer as well as the possibilities of the ISDN card. Most passive cards are limited by the supported IO addresses (e.g.: Teles 16.x: only 3 addresses are legally possible), and the total usage of interrupts (every card needs one).

To use more cards, the ICN card may be your choice. It has no interrupts, a more flexible port configuration and the driver places the shared memory area of all ICN cards at the same address. The card memory is shown only as needed. Therefore, one can use as many cards are there are slots.

If you really need a lot of ports, then eventuelly, a S2M card might be interesting for you, see question hardware_s2m.

Note that by default, i4l treats all available cards as a pool, first using all channels on the first card, then all on the second card, and so on. To change this, use the isdnctrl bind (not pppbind) command.

Also note, that you'll have to use modules for more than two cards, to pass all arguments.

5.10 hardware_teles: What should I know about before buying an ISDN card from Teles?

First the latest news: The Teles card 16.3c has a crippled FIFO, therefore it is required to use AT&B1024 when using the ttyI* devices (if the remote side still send packets with more than 1024 bytes it will not work - unfortunately many CAPIs use 2048 bytes as default). The latest Teles PCI card needs the netjet driver, the teles driver will NOT work (that card identifies itself as 'TigerJet Tiger300' when doing a cat /proc/pci).

Now some comments about Teles in general (these is the personal opinion of the author of this FAQ, please blame nobody else than me):

Teles' business practices are very customer- and developer-unfriendly when compared to those of other companies. Naturally, the developers give priority to cards for which support is available, and where the specifications are freely available.

So far, Teles has had a very unfriendly attitude towards the i4l developers. No support has ever been received from them, and they don't publish any information about how to access their card. The developers have invested a lot of private effort into getting this card to work from the beginning without receiving any support. The driver has been a complete private effort. Yet, Teles has bragged on their web site that their cards run under Linux, without giving proper credit.

Even companies that buy Teles cards and resell them under their own name have not been able to improve the support. This has lead to the situation where a re-branding company (!) itself had to go through the effort of obtaining approval to legally use i4l in Germany on a Teles card.

From a customer point of view, check out the prices for their hotline before you buy any hardware from them! The author of the FAQ refuses to use any hotline that charges 216,- DM per hour. Reports about quality and waiting time have not always been favorable.

Warning: Teles has often changed their cards without notice, while still using the same name. When you buy a Teles card, you may find out that your brand-new card can not be supported by i4l! (As is currently the case...)

The developers will try to support new Teles cards when information about how to access it becomes available, and when they have no other priorities. Of course you can always send a patch.

5.11 hardware_icn: What is special about the ICN card?

This was the first active card supported by isdn4linux. The manufacturer has always supported i4l developers ( http://www.think.de/). The ICN does not need any interrupt (polling), therefore a PC can be equipped with many of them without any interrupt conflicts. The newest firmware should be available at ftp://ftp.think.de/pub/isdn4linux/firmware/. Unfortunately, the ICN is not produced any more.

5.12 hardware_crossedcable1: If i4l uses one B-channel then the other one will be blocked (incoming as well as outgoing)...

This behavior is typical for a cable with confused a/b wiring. Some NT from Quante had a wrong labeling. They caused exactly the mentioned behavior if the PBX was connected to the plug of the NT and the ISDN card to the pins of the NT. As soon as some device activates the bus the other one can no longer get through.

5.13 hardware_crossedcable2: How can I test whether a a/b cable pair has been crossed?

This question assumes that you are connected by an internal bus that you installed, attached directly to the NT (without using an RJ45 cable).

The easiest way to test it is to buy a little cable tester (the author of this FAQ got one from Conrad Electronics in Germany for 29,- DM - just follow the simple instructions).

Otherwise you have a bit more work. Switch line a1 and b1. If it doesn't work, put them back and switch a2 and b2. If it still doesn't work, try switching them both. As long as {a|b}1 and {a|b}2 are kept, nothing can break. If you want to be sure, before plugging it in measure between pins 4 and 5 and between Pins 2 and 6 on the socket; there should be no current, but between 3 and 4 and between 6 and 5 should be 40 V, 6 and 3 positive.

With the Western plug this works similar. 4 lines are used:

| | | | 
| | | |
1 2 3 4
Then you can try to switch (1 with 4) or (2 with 3) or both. Never switch the outer with the inner lines - this would cross the RX and TX lines and nothing will work.

Check the Cable FAQ for more details on which line should be connected how.

If both devices are attached via RJ45, then one of the cables has been twisted. That usually happens if one of the RJ45 plugs has been attached upside-down (a1/b1 are inside, a2/b2 are outside, so the order of the sending/receiving pairs is maintained), then you just need a new plug and of course pliers for the RJ45, old plug off, and new plug (in the right direction) on.

5.14 hardware_pbx: i4l is working on the internal bus of a PBX. Any problem?

Many PBX run non-standard ISDN protocolls on their internal bus. This may cause i4l to print warnings when it encounters unexpected frames (some old versions even crash). Also, they may run 1TR6 protocoll by default, instead of Euro ISDN on their internal bus. You have to configure i4l (or the PBX) accordingly, best is you try both on the same or similar protocolls.

Also the MSN may be different than you expect. Check several versions, one digit, or two digits, or whole MSN. Best is you call some device (e.g. ISDN telephone) on the internal bus and check what i4l writes into the log file.

5.15 hardware_telestrouble: The PNP tools done work with my Teles 16.3 PNP card!

It's probably not a Plug 'n Play card at all - even though Teles now prints PNP on all their card and packaging. The difference is easy to recognize: a real Teles PNP card no longer has the (tiny) Dip switches on the card to set the IO addresses.

5.16 hardware_elsacabletrouble: On my ELSA card, the LED for the loss of the TEI often blinks. My connections are also often disrupted...

These blinking LEDS are often caused by a bad cable or a too long or unterminated SO bus.

5.17 hardware_elsairq: My ELSA Quickstep 1000 ISA card produces very many interrupts with the HiSax driver. Is this normal or a problem with the HiSax driver?

This is normal. The ELSA Quickstep 1000 ISA card has a hardware timer on the card which can not be disabled by software. You have to modify the card hardware to get rid of it. Check with Karsten Keil for this: keil@isdn4linux.de


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