diff --git a/FAQ/i4lfaq.sgml b/FAQ/i4lfaq.sgml index 16b72c69..14b04bce 100644 --- a/FAQ/i4lfaq.sgml +++ b/FAQ/i4lfaq.sgml @@ -4,7 +4,7 @@ FAQ for isdn4linux <author>Matthias Hessler (<tt><htmlurl url="mailto:hessler@isdn4linux.de" name="hessler@isdn4linux.de"></tt>) -<date>v2.0.51, 3. December 2000 +<date>v2.0.52, 30. December 2000 <abstract> If you are reading this FAQ online, you may consider downloading the whole thing, and reading it offline (much cheaper). To download the latest @@ -575,8 +575,8 @@ difference: <ref id="glossary_pointtopointmode" name="glossary_pointtopointmode" <label id="feature_ntmode"> <p> Yes, isdn4linux does support it, but only for a few special cards. -See question <ref id="feature_crossedcable" name="feature_crossedcable"> for details. In the -glossary there is more information on what the NT mode is: +See question <ref id="feature_crossedcable" name="feature_crossedcable"> +for details. In the glossary there is more information on what the NT mode is: <ref id="glossary_ntmode" name="glossary_ntmode">. <sect1> feature_crossedcable: Can isdn4linux directly connect two @@ -591,8 +591,13 @@ Use the following command to start the ISDN card in NT mode: <code> hisaxctrl <id> 98 1 </code> -However, make sure that the crossed cable is terminated even if it is -very short. Some HFC card already have jumpers for termination. +Make sure that the crossed cable is terminated even if it is very short. +Some HFC card already have jumpers for termination. + +However, this will only give you the physical connection. Up to now +isdn4linux does not (yet?) implement the higher level ISDN protocol DSS1 +(this means that isdn4linux can not pretend to an ISDN device that it is +an ISDN exchange, and give it the proper ISDN commands). <sect1> feature_lcr: Can isdn4linux do least cost routing (LCR)? <label id="feature_lcr"> @@ -852,8 +857,7 @@ Note: <item>Eicon Diva U interface not tested <item>Some cards do not work when compiled into the kernel, only when <item>Asuscom card: please note that the ISA version is a different type -(12) then the PCI version (35 or 36)! -started as modules +(12) then the PCI version (35 for HFC chip or 36 for Winbond chip)! <item>To distinguish between HFC-PCI and PCI/Winbond, have a look at the output of <tt>cat /proc/pci</tt>. You have HFC-PCI if you have a line saying "Master capable" for your card. @@ -949,6 +953,16 @@ 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. +<sect1> hardware_irqsharing: Can the isdn4linux driver work with shared +interrupts? +<label id="hardware_irqsharing"> +<p> +Yes, the drivers have been written to work with shared interrupts. However, +at least for the AVM Fritz!PCI card occasional problems have been reported +for motherboards with a BIOS bug (DFI motherboards K6BV3+, P5BV3+ K6XV3). +Try to disable the BIOS option <tt>CPU to PCI WRITE Buffer</tt> in those +cases as a workaround. + <sect1> hardware_s2m: Which S2M cards are supported? <label id="hardware_s2m"> <p> @@ -1116,14 +1130,15 @@ Cable abcd --abcd-- <label id="hardware_sedlbauer"> <p> It is a semiactive card based on the ISAR chipset which supports -sending/receiving faxes. It is special in that you use it with HiSax which -normally works only for passive cards. However, as all active card you have -to load its firmware (in this case after loading HiSax) from the file -ISAR.BIN, which is part of the isdn4k-utils. +sending/receiving faxes and an analog modem up to 14400. It is special in +that you use it with HiSax which normally works only for passive cards. +However, as all active card you have to load its firmware (in this case +after loading HiSax) from the file ISAR.BIN, which is part of the +isdn4k-utils. Please note that compression (V42bis, MNP) are not implemented in firmware, -and therefore not supported. The ideal init string for the card to allow -modem dialin is <tt>AT%C0\N0</tt>. +and therefore not supported when using the analog modem. The ideal init +string for the card to allow modem dialin is <tt>AT%C0\N0</tt>. <sect1> hardware_teles: What should I know about before buying an ISDN card from Teles? @@ -1188,6 +1203,10 @@ ISA/PNP card have the same type (27), hisax will assume an ISA/PNP card if you pass an io address, and a PCI card if you do NOT pass an io address. Make sure to give the parameters properly. +If the interrupt for the card is shared with other devices and your card does +not work, then there could be an issue with the motherboard. See question +<ref id="hardware_irqsharing" name="hardware_irqsharing"> for this. + One very interesting thing: the Fritz! card is currently the only passive card for which a capi driver exists. As a result, it can be configured to fax. See question <ref id="feature_capi" name="feature_capi"> and @@ -1694,9 +1713,18 @@ The old Teles driver, on the other hand, will appear to start even if it is not working. See the questions under Troubleshooting Teles. <item>Make sure you configured the ISDN driver either as modules, or you compiled them into the kernel - never both. -<item>Try calling with a telephone. The number should be shown in -/var/log/messages. Otherwise, perhaps the driver was incorrectly -started?! +<item>Try calling your dialin number with a telephone. The number should be +shown in <tt>/var/log/messages</tt>. Check for a line like this: +<code> +Call from 0,1,2345 -> 6789 +</code> +This means that on channel 0 a call from 2345 with service indicator (SI) 1 +(1 = voice; data would be 7) to MSN 6789 was received. Now at least you know +that you have to configure your MSN to 6789 (or whatever other number you +find there), and that your isdn4linux kernel driver understand ISDN +commands coming from your ISDN card properly. If instead of the number 2345 +you find a 0, then your ISDN provider does not pass you the caller id. +If you don't find such a line: perhaps the driver was incorrectly started?! <item>As a next step we'll try to get the telephone or fax to ring by dialing ourself using a ttyI device with minicom. First we have to change the service recognition with the <tt>ATS18=1</tt> command to audio. Now you can get the @@ -2410,6 +2438,8 @@ Check out these special dialout features: see section <ref id="chargeint" name="chargeint">. <item> Dialout on more than 1 channel at the same time: see section <ref id="2channel" name="2channel">. +<item> Dialout on one specific channel: +see question <ref id="dialout_fixedchannel" name="dialout_fixedchannel">. <item> Callback: see section <ref id="callback" name="callback">. </itemize> @@ -2505,6 +2535,19 @@ now only dial out with MSN 333 on <carddriver1>, while dialout on 3 will now only dial out with MSN 777 on <carddriver2>. </itemize> +<sect1> dialout_fixedchannel: How can I force HiSax to always dial out on +a specific B channel? +<label id="dialout_fixedchannel"> +<p> +HiSax has an undocumented feature for this. Add 'P1' in front of the dialout +phone number for the first B channel, or 'P2' for the second B channel, like +this: +<code> +isdnctrl addphone <device> out P1<your_out_number> +</code> +Please note that then a dialout will fail when another device already uses +the second B channel. + <sect1> dialout_bind: A dns query causes bind to dial out. Why does it take about a minute before it is answered? How do I work around it? <label id="dialout_bind"> @@ -3576,7 +3619,7 @@ From time to time, the name server will query its forwarder, which will trigger a dialout. Since your ISP uses dynamic ip addresses, the request is sent out with the wrong ip address at startup of the dial-in connection. Therefore, no answer will be received. Bind waits for one minute -before resubmitting. Since your line has come down in the mean time, this +before resubmitting. If your line has come down in the mean time, this will trigger a new dialout, resulting in a different ip address, and so on... For a workaround to this problem you can shorten the retransmission time @@ -3645,28 +3688,43 @@ Only a home page that Netscape is able to load immediately (e.g. dialout. Alternatively you can also set up a cache daemon that saves pages that are often needed. -A proxy should not cause a dial out, even when the complete name is -entered. Only when a new proxy is given does Netscape do a DNS -lookup (and in this special case cause a dialout. -However, on 17 Mar 97 Steffan Henke -<tt><htmlurl url="mailto:henker@informatik.uni-bremen.de" name="henker@informatik.uni-bremen.de"></tt> -wrote: -<quote> -Unfortunately reality has caught up with us. I've heard that -Netscape now in version.4.02 really does establish a -connection... -</quote> +Second check your proxy settings. When giving a complete name instead of an +ip address, Netscape may try to do a DNS lookup to resolve the name to an +ip address on startup. In this case provide Netscape with an ip address. + +Another thing is that Netscape tries to contact its news server. If you don't +want to use this feature then you can enter the name Netscape uses for lookup +(probably 'news') in your local DNS or in your /etc/hosts, and let it point +to localhost. <sect1> dod_closeipconnect: After closing the line, I discover with <tt>netstat -nt</tt> that IP connections are still open. How can I close these manually? <label id="dod_closeipconnect"> <p> -You can bring the interface &dquot;down&dquot; then back &dquot;up&dquot;. When -you do this, it will try to dial out. But if you have removed the outgoing -telephone number, then &dquot;no outgoing number...&dquot; appears in the -syslog, and as soon as the interface is &dquot;up&dquot;, all connections will -be closed. +This may only work with the RST-Revoking patch (mentioned in question +<ref id="dod_causes" name="dod_causes">): You can bring the interface +&dquot;down&dquot; then back &dquot;up&dquot;. When you do this, it will +try to dial out. But if you have removed the outgoing telephone number, +then &dquot;no outgoing number...&dquot; appears in the syslog, and as +soon as the interface is &dquot;up&dquot;, all connections will be closed. + +You can prevent those open IP connections to trigger new dialouts if you +add a special firewall rule in <tt>/etc/ppp/ip-down</tt>, and remove it +in <tt>/etc/ppp/ip-up</tt>. This firewall rule drops all tcp packets +which are not in SYNSENT state. Add this in <tt>/etc/ppp/ip-down</tt> for +a 2.2.x kernel: +<code> +ipchains -A output -j DENY -p tcp -i <interface> ! -y +</code> +Add this in <tt>/etc/ppp/ip-up</tt>: +<code> +ipchains -A output -j DENY -p tcp -i <interface> ! -y +</code> +(As is the case for all firewall rules: it is best to put this into a +separate script which is called with either a start or a stop parameter.) +Please note that this firewall rule only matches whole packets, no fragments. +A fragment will always bypass the firewall and trigger a dialout. <sect1> dod_onlineoncrash: Is it possible that even with a crashed computer a ISDN connection remains open (and the charge units accumulate)? @@ -4050,7 +4108,11 @@ This will simulate a call for MSN1 on the configured channel (0 or 1) and the other as a dialup line? <label id="leased_splitline"> <p> -Yes, you can. But you have to make sure that you use the correct channel. +Yes and no. You can configure HiSax for both at the same time, however you can +only use one of them at any point in time (you have to switch off the leased +line before dialing out). It may work occasionally simultaneously, however +the driver has not been written for it so the results are not deterministic. +Also make sure that you use the correct channel. <!-- Dialin @@ -4594,13 +4656,13 @@ be able to hear something. <sect1> audio_dtmf: How can I improve the recognition of (DTMF) dial tones? <label id="audio_dtmf"> <p> -You can adjust the parameters DTMF_THRESH and H2_THRESH in file +You can adjust the parameters DTMF_TRESH, SILENCE_TRESH, and H2_TRESH in file <tt>linux/drivers/isdn/isdn_audio.c</tt>. A DTMF tone is recognized -if the amplitude of the correct frequency is larger than DTMF_THRESH +if the amplitude of the correct frequency is larger than DTMF_TRESH and the amplitude of the second harmonian frequency is smaller than -H2_THRESH. +H2_TRESH. If a dial tone is recognized when no dialing took place, try to increase -DTMF_THRESH and/or decrease H2_THRESH. However, test with many +DTMF_TRESH and/or decrease H2_TRESH. However, test with many telephones - the current parameters were already set after some tuning.