**** BEGIN LOGGING AT Mon Dec 19 02:59:58 2005
Dec 19 16:08:52 <lennert> another idea
Dec 19 16:09:03 <lennert> an ISDN PRI/BRI interface with the S3 board
Dec 19 16:12:33 <lennert> i'm wrestling with an ISDN BRI 'modem' right now.. and god, i'm almost starting to believe that it would be easier to implement such a beast myself
Dec 19 16:21:40 <lennert> E1 should be easy enough to interface with
Dec 19 16:21:44 <lennert> 2048000 bits per second
Dec 19 17:27:31 * [g2] would _LOVE_ to have an E1/T1 card
Dec 19 17:27:44 <[g2]> I've got a quad T1 card with a PCI bridge
Dec 19 17:28:08 <[g2]> the chip _may_ be quad t1/e1/j1
Dec 19 17:28:19 <lennert> what does the card let you do?
Dec 19 17:28:33 <lennert> do you have raw access to the D channel?
Dec 19 17:28:39 <lennert> (i.e. can you speak LAPD?)
Dec 19 17:28:45 <[g2]> D channel ?
Dec 19 17:29:14 <lennert> T1 is (iirc) 23 Bearer channels (64kbit/s) and 1 D channel (16kbit/s) for signaling
Dec 19 17:29:32 <[g2]> you're confusing it with E1
Dec 19 17:29:36 <lennert> no
Dec 19 17:29:41 <lennert> E1 has 30 bearer channels
Dec 19 17:29:47 <[g2]> T1 is 24 channels
Dec 19 17:30:00 <lennert> one of which is reserved
Dec 19 17:30:02 <[g2]> There's some signalling in the 8Kbits
Dec 19 17:30:12 <[g2]> there are none reserved in clear channel
Dec 19 17:30:50 <[g2]> There's framing and signalling in the 8K bits sequence
Dec 19 17:30:52 <lennert> hmmok
Dec 19 17:30:57 <[g2]> it's 193 bits every 8K
Dec 19 17:30:59 <lennert> wikipedia is wrong then :)
Dec 19 17:31:04 <[g2]> well 8K a second
Dec 19 17:31:19 <[g2]> 8K*193 = 1544400
Dec 19 17:31:20 <lennert> yeah, 8000 times 193
Dec 19 17:31:30 <lennert> 193 = 24 * 8 + 1
Dec 19 17:31:39 <[g2]> exactly
Dec 19 17:31:49 <[g2]> then there ESF and D4 signalling
Dec 19 17:31:58 <lennert> extended superframe
Dec 19 17:32:01 <[g2]> D4 being the older
Dec 19 17:32:02 <lennert> haven't heard of D4
Dec 19 17:32:32 <[g2]> I'd imagine ESF clear channel is used 99.99% of the time now
Dec 19 17:32:49 <[g2]> the other big item is the T1 clocking
Dec 19 17:33:42 <[g2]> I think the C company sells 8 port T1 broadband routers for like 3K
Dec 19 17:34:14 <lennert> the wikipedia page on ISDN says it uses 23 B channels plus one D channel
Dec 19 17:34:18 <lennert> (when run over T1)
Dec 19 17:34:24 <lennert> what else can you run over T1?  SS7?
Dec 19 17:34:35 <[g2]> I can bolt 2 of the quad T1/PCIs onto a Loft and having a broadband router
Dec 19 17:34:47 <[g2]> yes ISDN is it's own animal
Dec 19 17:35:08 <[g2]> they are probably running the signalling in one of the channels
Dec 19 17:35:22 <lennert> yeah
Dec 19 17:35:30 <lennert> but the D channel on PRI ISDN is still only 16kbit/s (i think)
Dec 19 17:35:42 <[g2]> yes... the cobwebs clear a little and the D channel comes back and the B channels are the bearer channels (data)
Dec 19 17:36:13 <lennert> E1 has 30 B channels and one D channel
Dec 19 17:36:35 <lennert> E1 is 8000 times per second (32 timeslot times 8 bits)
Dec 19 17:36:39 <[g2]> Data usually runs with HDLC encoding in 7 or 8 bits (8 bits in clear channel)
Dec 19 17:36:57 <[g2]> yes I'm familiar with E1
Dec 19 17:37:21 <[g2]> a cell system I worked on for 4-5 years had an Alcatel switch and the A-Interface
Dec 19 17:37:47 <lennert> HDLC?
Dec 19 17:37:56 <lennert> it says here the D channel runs Q.921 (LAPD)
Dec 19 17:37:56 <[g2]> 16 and sometimes 31 are the signalling channels
Dec 19 17:38:19 <lennert> yeah, TS0 is framing, and TS16 is mentioned as signalling timeslot
Dec 19 17:39:00 <lennert> ah
Dec 19 17:39:09 <lennert> LAPD is a cousin of HDLC
Dec 19 17:39:47 <[g2]> the IXP425 has HDLC on chip
Dec 19 17:40:06 <lennert> intewesting
Dec 19 17:40:29 <[g2]> there's bit stuffing and de-stuffing
Dec 19 17:40:42 <[g2]> it can be done in an FPGA pretty easily
Dec 19 17:41:03 <[g2]> especially at the rate we are talking about
Dec 19 17:41:38 <[g2]> But the T1/E1 framer/deframer are quite important
Dec 19 17:41:53 <lennert> yeah
Dec 19 17:42:02 <lennert> E1 is 2Mb/s
Dec 19 17:42:14 <lennert> HDB3 looks easy enough to implement too
Dec 19 17:44:19 <[g2]> any idea what the cheapest hardcore costs in a Xilinx ?
Dec 19 17:45:42 <lennert> hardcore
Dec 19 17:45:43 <lennert> you mean a ppc?
Dec 19 17:45:59 <lennert> what exactly do you mean?
Dec 19 17:46:03 <lennert> you want to buy IP or something?
Dec 19 17:47:15 <[g2]> yeah PPC
Dec 19 17:47:34 <[g2]> The cheapest Virtex
Dec 19 17:47:42 <[g2]> or is V4 Pro
Dec 19 17:47:45 <lennert> xc2vp2 doesn't have a ppc, right?
Dec 19 17:48:47 <lennert> xc2vp4 has 1 ppc
Dec 19 17:49:42 <lennert> avnet sells XC4VP4-5FG256s in quantities of 90 for $113 each
Dec 19 17:49:44 <[g2]> the V4s are probably cheaper no ?
Dec 19 17:49:55 <lennert> sorry, XC2VP4-5FG256s
Dec 19 17:50:03 <lennert> that's a 16x16 BGA package though
Dec 19 17:50:08 <lennert> hmmm
Dec 19 17:51:03 <lennert> xc4vfx12 is the smallest virtex 4 with a PPC
Dec 19 17:51:36 <[g2]> lennert you know about these guys right ?
Dec 19 17:51:37 <lennert> avnet has those for $157 in single quantities
Dec 19 17:51:50 <lennert> that'll get you a XC4VFX12-10SF363CES
Dec 19 17:51:55 <lennert> [g2]: which guys?
Dec 19 17:51:58 <[g2]> http://suzaku-en.atmark-techno.com 
Dec 19 17:52:28 <[g2]> Suzaku
Dec 19 17:52:48 <lennert> yeah
Dec 19 17:52:55 <lennert> what do they cost though?
Dec 19 17:53:21 <[g2]> I think they were only $350 1.5-2 years ago
Dec 19 17:53:21 <lennert> the suzaku v2pro board indeed has the XC2VP4-FG256
Dec 19 17:53:43 <lennert> 'only $350'? :)  i can get the digilent xc2vp30 board for $299!
Dec 19 17:54:38 <[g2]> well this was a couple years ago and that's the commercial pricing which is like 1600 for your board correct ?
Dec 19 17:55:19 <lennert> true.. $1599
Dec 19 17:55:48 <[g2]> it's _really_ important to be aware of educational discounts because they _are_ real too
Dec 19 17:56:01 <[g2]> but it's not really fair to compare different programs
Dec 19 17:57:17 <lennert> you're right
Dec 19 18:14:12 <lennert> it should be possible to do AMI/HDB3 even with the spartan3 board and half a dozen external components
Dec 19 18:18:57 <[g2]> yeah AMI/B8ZS are the two major formats iirc
Dec 19 18:20:27 <lennert> B8ZS for T1, HDB3 for E1
Dec 19 18:20:31 <lennert> AMI for BRI
Dec 19 18:20:38 <lennert> acronym overload
Dec 19 18:36:15 <[g2]> B8ZS is clear channel for T1
Dec 19 18:36:33 <[g2]> AMI is robbed-bit or 7-bit iirc
Dec 19 18:38:46 <lennert> AMI is clear for BRI IIRC
Dec 19 18:48:12 <[g2]> I think most of ISDN is clear
Dec 19 18:51:54 <lennert> yeah
Dec 19 18:52:09 <lennert> T-carrier wasn't but now apparently is
Dec 19 18:52:35 <lennert> ok, so what is a good BRI ISDN card for linux?
Dec 19 18:52:42 <lennert> i'm not looking for a Terminal Adapter
Dec 19 18:53:05 <lennert> but something that gives access to the entire gamut of I.430 capabilities
Dec 19 19:32:27 <[g2]> dunno
Dec 19 19:39:40 <lennert> okay
Dec 19 19:40:03 <lennert> now i need a way of figuring out whether an incoming call is rejected by the exchange or the local equipment
Dec 19 19:40:13 <lennert> what is the easiest way of sniffing the BRI? :)
Dec 19 19:43:24 <[g2]> is it brought in on a T1 ?
Dec 19 19:45:57 <lennert> on an E1
Dec 19 19:46:06 <lennert> hmm no, sorry
Dec 19 19:46:10 <lennert> there is an incoming E1
Dec 19 19:46:19 <lennert> and there is also a regular incoming BRI (2xB+D)
Dec 19 19:46:27 <lennert> and the modem is on the BRI
Dec 19 19:55:55 <lennert> well
Dec 19 19:56:12 <lennert> i think the people here want me to build it
Dec 19 19:56:16 <lennert> i.e. an fpga-based BRI interface
Dec 19 19:56:43 <lennert> shudder
Dec 19 19:56:49 <lennert> am i going to take this job or let it pass :P
Dec 19 20:01:12 <lennert> 4AM now.. hard to make decisions
Dec 19 20:10:07 <bullet> 4PM now.. :)
Dec 19 20:11:10 <lennert> 4:11
Dec 19 20:11:29 <lennert> bullet: where are you, in .ch?
Dec 19 20:11:50 <bullet> yah, switzerland
Dec 19 20:14:13 <bullet> you asking where exactly from?
Dec 19 20:20:13 <lennert> the Netherlands
Dec 19 20:20:19 <lennert> oh, sorry
Dec 19 20:20:25 <lennert> no, just wondering if you were really from .ch
Dec 19 20:20:34 <lennert> as.. it's 4:20AM here, and you say it's 4PM there
Dec 19 20:20:41 <lennert> so you should be in australia or something :)
Dec 19 20:21:00 <bullet> hehe
Dec 19 20:21:17 <bullet> lol, i mixed AM/PM
Dec 19 20:21:38 <bullet> well, we don't normally use am/pm, so pardon me
Dec 19 20:29:06 <lennert> yeah
Dec 19 20:29:10 <lennert> we don't really use am/pm either
Dec 19 20:30:53 <bullet> is ISDN/BRI commonly used in nl? (it is down here)
Dec 19 20:31:10 <lennert> but a lot of american folk use am/pm so i got used to it
Dec 19 20:31:45 <lennert> i don't see a lot of isdn here in .nl
Dec 19 20:31:54 <lennert> at least, consumers don't
Dec 19 20:32:10 <lennert> company pbx'es usually have PRIs
Dec 19 20:32:20 <lennert> most consumers are still on good ole' POTS
Dec 19 20:32:29 <lennert> i think .nl might be a bit of an exception
Dec 19 20:32:41 <lennert> in .de, i think ISDN is also more popular than it is in .nl
Dec 19 20:32:57 <bullet> possible. but it's "dying" slowly
Dec 19 20:33:32 <lennert> dying where, in .de ?
Dec 19 20:33:54 <bullet> yeah. because of adsl/voip/mobile/...
Dec 19 20:34:01 <lennert> now that i've looked into it, it just looks better than POTS in every possible way
Dec 19 20:34:04 <lennert> oh...
Dec 19 20:34:07 <bullet> at least, the market stopped growing a while ago
Dec 19 20:34:11 <lennert> i thought people were converting back from isdn to pots!
Dec 19 20:34:21 <bullet> yeah, that too
Dec 19 20:34:26 <lennert> damn, that's a shame
Dec 19 20:34:39 <lennert> isdn is just sweet(tm)
Dec 19 20:34:46 <lennert> doable with a handful of components
Dec 19 20:34:54 <bullet> yeah, it is. i actually have isdn :)
Dec 19 20:35:08 <lennert> i don't
Dec 19 20:35:15 <lennert> and it's kind of hard to convert my pots line since i have adsll
Dec 19 20:35:21 <lennert> i first have to get adsl disabled
Dec 19 20:35:24 <lennert> then convert from pots to isdn
Dec 19 20:35:27 <bullet> ugh
Dec 19 20:35:30 <lennert> then get adsl re-enabled
Dec 19 20:35:35 <lennert> or at least, that's what i've been told
Dec 19 20:35:43 <lennert> i can't live without my adsl ;p
Dec 19 20:36:02 <bullet> in .ch, it's even wors. you need two different modems for pots/isdn adsl
Dec 19 20:36:11 <lennert> i think it's the same here
Dec 19 20:36:12 <bullet> annex-a vs. annex-b
Dec 19 20:36:22 <lennert> (but i'm not sure)
Dec 19 20:36:26 <bullet> in germany, it's all annex-a, i think
Dec 19 20:36:29 <lennert> so i'd have to change my modem as well..
Dec 19 20:36:52 <lennert> at least, when you sign up for adsl here, they ask if you have pots or isdn
Dec 19 20:36:54 <bullet> hmm, no, it's annex-b
Dec 19 20:37:06 <lennert> and then mention that if you get it wrong, it won't work, or something
Dec 19 20:38:26 <lennert> http://zylamp.zyxel.nl/news/press.php?SN=7
Dec 19 20:38:30 <lennert> i think that's the one i have
Dec 19 20:38:31 <lennert> and it's annex a
Dec 19 20:38:41 <lennert> hmm, wrong page
Dec 19 20:39:30 <lennert> can't find it now
Dec 19 20:41:47 <bullet> well, that modem could be using a ti ar7 chip, which does both, afaik
**** ENDING LOGGING AT Tue Dec 20 03:02:32 2005