From owner-freebsd-isdn Wed Oct 17 11:42:43 2001 Delivered-To: freebsd-isdn@freebsd.org Received: from smtp.kdt.de (ns2.kdt.de [195.8.224.2]) by hub.freebsd.org (Postfix) with ESMTP id 49FCF37B403 for ; Wed, 17 Oct 2001 11:42:36 -0700 (PDT) Received: from jocelyn.sub-etha.wtal.de (line8f28.kdt.de [213.240.143.40]) by smtp.kdt.de (8.8.8/8.8.8) with ESMTP id UAA28398 for ; Wed, 17 Oct 2001 20:42:33 +0200 Received: from marie.sub-etha.wtal.de (marie.sub-etha.wtal.de [213.240.145.124]) by jocelyn.sub-etha.wtal.de (Postfix) with ESMTP id 1F8F010 for ; Wed, 17 Oct 2001 20:24:52 +0200 (CEST) Received: by marie.sub-etha.wtal.de (Postfix, from userid 1501) id 602E06510; Wed, 17 Oct 2001 20:21:51 +0200 (CEST) Date: Wed, 17 Oct 2001 20:21:51 +0200 From: Ignatios Souvatzis To: freebsd-isdn@freebsd.org Subject: Re: NetJet-S and DOV Message-ID: <20011017202151.B3144@beverly.kleinbus.org> References: <004301c155e1$8007ec50$020aa8c0@aims.private> <20011017140600.C21633@tmp.com.br> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011017140600.C21633@tmp.com.br>; from prallon@tmp.com.br on Wed, Oct 17, 2001 at 02:06:00PM -0200 Sender: owner-freebsd-isdn@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Wed, Oct 17, 2001 at 02:06:00PM -0200, Sergio de Souza Prallon wrote: > > I wrote this driver for my personal use here in Brazil. Here, the ISDN > B-channels are 8-bit clean. If I understand Traverse's tech staff, DOV > consists in declare in the call-setup (in the D-channel) packet that > you want the B-channel to be Voice Capable instead of Data Capable. That > was because of diferent charge prices made by some of the Telcos. > Unfortunately, most of the terminal servers in use in Australia are Ascend > and they have a `feature' that if they receive a Voice call, they only > take 7 out of every 8 bits of the traffic (because Voice in America is > sampled with 7 bits) EVEN IF THEY CARRY HDLC FRAMED DATA. A Telco could even use some voice compression method behind your back and transmit 2 voice channels over one 64 kilobit/s link, if you declared you want to transmit voice.... But about the 7 of 8 bit part - the US use ulaw encoding - don't they? thats a 14 bit into 8 bit compression - you need an 8bit channel to transport it. Unless they are sampling it at 7 kHz sample rate, but famous US ISDN hardware, e.g. the audio chip used by (now ancient) SUN workstations, only supported 8 kHz 8-bit uLAW-encoding. Regards, -is To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message