Can't hurt to check how much it's going to cost for electricity. Rate per kWh range from a low of 7.06 (WV) cents to a high of 30.13 (HI) cents as of April 2008. National Average is 10.97 cents.
These rates are from the
EIA - Official Energy Statistics from the US Government
If you already leave your PC on, say a Media center used as a PVR, you're already paying for the electricity, so it won't make any difference.
Don't forget to adjust these figures to subtract the time you usually have the PC on. If you use the PC 4 hours a day for example, multiply these numbers by 20/24 to see how much additional it will cost to leave the PC running.
Keep in mind even a high end system will use a lot less power when sitting idle; a video card that uses 100 watts drawing 3d images during a game may use less than 30 watts sitting idle.
(Watts X 24 X 365)/1000=kWh/year (Watts X 8.76)
Divide kWh/year by 12 for kWh/month (Watts X 0.73)
Code:
Electricity cost per month
Watts Low US New High
Used West Va AVG England Hawaii
$/kWh-> $0.0706 $0.1097 $0.1689 $0.3031
50 $2.58 $4.00 $6.16 $11.06
100 $5.15 $8.01 $12.33 $22.13
150 $7.73 $12.01 $18.49 $33.19
200 $10.31 $16.02 $24.66 $44.25
250 $12.88 $20.02 $30.82 $55.32
300 $15.46 $24.02 $36.99 $66.38
If you live in one of the more expensive regions, and have a high end system, you could probably justify buying a low end desktop, or even a laptop to dedicate to the magic jack.
And with a 2nd PC on 24/7 you have a handy place to back up your data on a daily basis
The 80kbps is the bandwidth used when active. It's more a function of the particular Codec used to convert the voice signal to VoIP packets than the particular VoIP provider.
you can check your internet connection for VoIP quality here:
http://www.testyourvoip.com. Lots of good info there as well. Many other test sites to be found, just google voip test call.
One thing I haven't found is if it supports pulse dialing, or only DTMF. I also can't find what the max Ringer Equivilance Number magicjack supports, or the actual ring voltage it generates. The minimum is 40 VAC by spec, but some of the older analog phones will barely ring at that voltage. They are much happier with 60-90 volts. They do say it works with standard analog phones though. If you have an old Western Electric Model 500 rotary phone laying around, it would be good to see how well it works.
Jerry