Date: Fri, 03 Jun 2005 18:17:33 +0200 From: Thomas Wintergerst <Thomas.Wintergerst@nord-com.net> To: freebsd-isdn@freebsd.org Cc: Steven Looman <steven@krx.nl> Subject: Re: Asterisk on FreeBSD + ISDN BRI Message-ID: <42A0829D.3090704@nord-com.net> In-Reply-To: <A1F9D453-B4EC-4887-8AA0-1C9C6FDADB5C@cubical.fi> References: <20050526202222.E2BD81EAE291@alice.turbocat.de> <20050527140607.GA41449@minerva.krx.nl> <DABECAF6-58C5-4F46-8C61-F71DBD12E675@cubical.fi> <200505281534.58499.hselasky@c2i.net> <A1F9D453-B4EC-4887-8AA0-1C9C6FDADB5C@cubical.fi>
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Hello Jussi, Juha-Matti Liukkonen wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 28.5.2005, at 16.34, Hans Petter Selasky wrote: > >> I know that Windows uses CAPI to support ISDN devices, but the >> problem there >> is that only one ISDN device is allowed at a time. So can CAPI handle >> more >> than one physical device per CAPI interface (/dev/capi20) ? > > > The CAPI specs (www.capi.org), part 2 section 8.5 (unix interface), > which is obviously written with Solaris in mind, says: > > "COMMON-ISDN-API's device name is /dev/capi20. To allow multiple access > by different UNIX processes, > the device is realized as a clone streams device." > > In the same section the CAPI_GET_PROFILE operation is defined to return > a 16-bit unsigned value for number of supported controllers. So > multiple clients for multiple controllers is possible, unless the > implementation somehow restricts it. Small correction: The message parameter CID is divided into an NCCI, a PLCI and a controller part. The controller part has 8 bits, the msb beeing a flag for addressing a headset. That delivers 127 usable controllers, each with 2 or 30 B-channels. I think, that is currently enough for existing machines. And the hint for a "clone device" should rather address the possiblilty to allow multiple applications CAPI access. The controllers themselves are all addressed by an application through the single device entry "/dev/capi20". > >>> On 27.5.2005, at 17.06, Steven Looman wrote: >>> >>>> The ability to use CAPI with cheap cards (like in Windows for >>>> example) sounds >>>> great as it would be easier to write multiplatform applications. >>>> >> >> I don't think that CAPI is fit for every situation. Putting things in a >> library on top of "isdnd" is going to be much more powerful than if one >> writes a dedicated CAPI-compatible telephony application? > > > CAPI is a lower-level thing than isdnd; it is more akin to i4b layer 3. > It allows moving call control logic to userspace processes - but more > improtantly, it is sort-of a standard. Which would potentially mean > binary compatibility with some lunix apps. Ack. Using CAPI one can use (nearly) all ISDN features. Other APIs mostly have some restrictions. But this flexibility also makes some things a little bit complicated (no example here ;-) ). [...] -- Regards, Thomas Wintergerst
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