I have been using Idefisk
on my stick for quite a while now, it used to be an IAX client only (IAX is usually only interesting to people running an asterisk server, as - unfortunately - only few providers offer services with this fine protocol).
Pleasant surprise: the latest version 2.0 can do also the more popular SIP protocol, so you actually have the best of two worlds! So far, I had only known of zoiper
for such an ability, and zoiper continues to be expiryware until today. Not so Idefisk
, which comes in two flavours - free and biz. The free version, however, has all it needs for the travelling voiper who needs that on his stick. The only reason for me to upgrade to biz would be for the G729 codec, not included in the free version. G729 is very useful on low bandwidth, and that you have to pay for it is normal - it is a commercial product.
I extracted the program from the downloaded installer using 7zip and put the two files in a folder on my stick. Haven't carried out too many tests yet for lack of time, but it looks very promising.
The interface actually looks almost identical to zoiper - there is clearly a relation between the two programs, although I continue to ignore what exactly this is.
For the first run, I would recommend to uncheck the option "Start with Windows" in the general options section. Unfortunately, it is checked on by default.
writes its settings to the application folder.
This is really a very nice program, and I would be happy to see it added to the DB.