A prototype VoIP client allowing users to make phone calls over the Internet will be unveiled next week. Device driver developer Dave Higton says he's ready to demonstrate a partially-complete RISC OS client that can call a PC running open source VoIP package Ekiga. His software, written in BASIC V on his Iyonix, is not ready to receive incoming calls.VoIP, or Voice-over-IP, breaks conversations up into packets of compressed data and sends them over a network, such as the Internet, allowing conversations to be held in real-time by two or more computer users. Crucially, a VoIP call is usually free, although payment is often required when connecting to a normal landline number.
A VoIP client requires two key components: one to manage and direct incoming and outgoing calls, and another to turn chat audio into data and vice-versa. Dave's software uses SIP for controlling connections and RTP for sending and receiving a conversation's audio. By using standard protocols, his program will be compatible with various VoIP packages available on other computer platforms.
Dave, best known for his USB hamster wheel and ROFS work, said he is prepared to make his client available if he can get it up to scratch.
He said: "If it works well enough, it's definitely something I would release.
"It's a standard SIP client, compatible with any other SIP client. At least, it will be when I've written and debugged more of the SIP interpreter.
"At the moment it's a technology demonstrator, but it can make a call to Ekiga on a computer on the same network. It can't receive calls yet; again, that's just extending the SIP interpreter. Audio is transported via standard RTP, and that very definitely works in both directions."
Dave also found a simple headset with microphone did the job and no other equipment is needed with his Iyonix. The audio-in is connected to the microphone and audio-out to the headphones.
He added: "The Iyonix doesn't require any external audio IO device or preamplifier, or anything like that; just a headset with microphone. I was surprised when I tried it.
"Subject to using the Iyonix's sound input system correctly, and subject to using a capacitor microphone, which is the most common type anyway, there is sufficient gain from the microphone to hold a normal conversation."
• Dave will show off his VoIP work to members of the Southampton Acorn users group on Tuesday October 9. The presentation will run from 7pm to 9pm at the Itchen College, Middle Road, Bitterne, in room S1. Entry is free.
Links
Previous coverage of VoIP on RISC OS