Hi Derek and Andrew, Thanks both for the feed back.
Andrew, echo is likly to be being caused by the complex impedance and E&M seperation. I've been learning a bit about it over the last couple of weeks because I was having problems with my new woosh phone service and my panasonic dect cordless. I spent some time talking with a friend who knows quite a bit about these things. Cheers Don On Sat, 2006-01-07 at 16:02, Derek Smithies wrote: > Hi, > I have "used" skype and other voip things for a while now. > > If you are receving echo from the other end, it suggests something is > wrong at the other end. Basically, it means that audio you are sending is > getting into the mic circuit of the remote endpoint. > > It can happen if the remote end is using a loudspeaker and microphone. > Your words are coming out the loudspeaker, and being detected by the > microphone, and then sent back to you. > > It can happen when the remote person uses the internal mic and speaker of > a laptop. > > The best way to eleminate echo is to get both ends to have headphones and > mics. This makes it hard for the audio to go from the "speaker" to the > mic. > > However, alsa can cause some problems. With the appropriate adjustment > inside alsamixer, you can get alsa to send audio from the output side of > things to the microphone side of things. > > If you are calling to a regular telphone with skype, all bets are off. If > the remote phone system is badly configured, you will get echo. > > There is plenty of dtmf decoder software available for linux that works > just fine. However, if the dtmf decoder software is asked to detect dtmf > in an audio stream that has been compressed/decompressed with a telephony > codec, all bets are off. This has been recognized as "not reliable". > > skype is heavy on the network - it tends to cause the conversation to > delay a bit when used over a dialup connection to the internet. > > Derek. > =============================================================== > On Sat, 7 Jan 2006, Andrew Errington wrote: > > > On Sat, 07 Jan 2006 08:16, you wrote: > > > Sounds fantastic! > > > > > > Have you had it up and running with Linux? > > > > > > I assume you can dial as well? As in, does the linux stuff have a dtmf > > > decoder software for the sound card (as I can see there's no dtmf > > > receiver built in to the hardware). > > > > > > What about incoming calls? Is there any ring generation at this point? > > > > > > Cheers Don > > > > "Sounds fantastic" might be an inappropriate comment. It seem to suffer > > from echo at the other end, which may be inherent in the design. > > > > I have not had it running with Linux, but all it is is an equivalent of a > > microphone and speakers, so is OS neutral. > > > > I don't know if there is DTMF detection in software for Linux, I downloaded > > and installed the Windows chat-cord code. This does detect and decode > > DTMF, so you can drive Skype with the telephone keypad. Bit flaky though. > > > > There is no ring generation (that's a bit tricky...). In all, worth the $5 > > and 30mins I spent building it, but not quite there yet. > > > > In other news, I just discovered Gizmo. This is a similar thing to Skype, > > but uses SIPphone and standard VOIP. It may be preferable to Skype for two > > reasons. > > > > 1) Uses open, standard protocols > > 2) Does not use excessive resources on your PC (apparently Skype uses your > > PC as part of its own network for processing and call routing.) > > > > Andy > > -- Don Gould
