From zarquin at ucc.asn.au Thu Oct 12 10:08:41 2006 From: zarquin at ucc.asn.au (Alwyn Lloyd) Date: Thu, 12 Oct 2006 10:08:41 +0800 (WST) Subject: [URC] AGM Meeting. Message-ID: We haven't had an AGM yet, So im proposing 12:30 on wed 25th of this month. I'm thinking it would be cool to organise some stuff to do over the summer break as well.. I'd be up for doing some stuff. Also, maybe some posters to get people to join/come?? Cheers, Alwyn From zarquin at ucc.asn.au Thu Oct 12 12:55:53 2006 From: zarquin at ucc.asn.au (Alwyn Lloyd) Date: Thu, 12 Oct 2006 12:55:53 +0800 (WST) Subject: [URC] AGM Meeting. In-Reply-To: References: Message-ID: Just to follow up, I have booked the meeting room for 12:30 on the 25th. Publicity should ensue. > > > We haven't had an AGM yet, > > So im proposing 12:30 on wed 25th of this month. > > I'm thinking it would be cool to organise some stuff to do over the summer > break as well.. I'd be up for doing some stuff. > > Also, maybe some posters to get people to join/come?? > > Cheers, > Alwyn > From davidb at ucc.gu.uwa.edu.au Wed Oct 18 10:51:17 2006 From: davidb at ucc.gu.uwa.edu.au (David Basden) Date: Wed, 18 Oct 2006 10:51:17 +0800 Subject: [URC] Phone patch circuit Message-ID: <20061018025116.GA12707@shikita.rcpt.to> Hi everyone, I'm wondering if I could get feedback on a circuit that I made to patch from a soundcard to a phone handset. It's REALLY not designed to be plugged into a PSTN line at all (for a start the battery would have to go ;-)), but just to look like a normal local-loop to the phone. There are plenty of circuits on the net to do this sort of thing, but the ones that don't use active components are all pretty dodgy looking. I haven't designned anything quite like this before, so if there is anywhere I have gone badly (or even slightly) wrong, let me know. Cheers, David 9V battery | | C1 R2 9k ohm +-----||||------------+----||-------+ +---+-----/\/\/---o Output to soundcard | | | | 10uF | | | phone o / } |#| { | C2 600 \ R1 } |#| { +--------||---o Input from soundcard handset o ohm / } |#| { 10uF | | | | +---------------------+-------------+ +--------/\/\/----o Signal GND T1 R3 150 Ohm T1 is a 600-600ohm line isolation transformer taken from a modem. It can't take more than a few uV before saturating, hence the caps. I really would have preferred a centre-tap transformer, but I couldn't easily find. 600 - 300/300 one. This one will give really good isolation anyhow ;-) C1 and C2 are polyester caps taken from the same modem, and should be large enough to not lose too much of the low-end voice frequencies. The output to the soundcard should idealy be a 10k ohm match. The input from the soundcard should idealy be a 1k ohm match. I've obviously gone more in favor of the higher impedence one being matched. Both inputs should see an inductive impedence. R1, R2 and R3 are all 1/2 W resistors. The phone handset is a current loop, matched at 600 ohm. Even with it showing as a short, there shouldn't be a large amount of current flowing across the 9V battery. From zarquin at ucc.asn.au Tue Oct 24 13:41:54 2006 From: zarquin at ucc.asn.au (Alwyn Lloyd) Date: Tue, 24 Oct 2006 13:41:54 +0800 (WST) Subject: [URC] Reminder: AGM Tommorow! Message-ID: Just a reminder the the URC's AGM is TOMMORROW at 12:30 in the Guild Meeting room. Bring your friends! :) [zar]