Ham Radio Repeaters Connected via EchoLink

I was testing my radio with some local repeaters and one of the friendly hams said my signal was pretty clear but that he was on EchoLink and couldn't be sure. That reminded me of a question in the Technician class test pool:

"How is access to an IRLP node accomplished?
B. By using DTMF signals"

Then I googled EchoLink and connected my radio. The process is really simple:

1) Enter a frequency (MHz) and tone (Hz) into my ham radio tranceiver
2) Press and hold the push to talk (PTT) button
3) Enter a node number using the keypad
4) Release the PTT button

This "telecommand" controls a  repeater near me to connect across the Internet to a repeater in another city. The remote repeater will announce that is has connected and then I hold my PTT and chat with operators in the remote city.

Apparently I can also download applications and connect directly from a computer or smartphone to a remote repeater. So it's not really even necessary to buy a radio to make use of your license. Things sure have changed since my grandpa showed me how he used his radio when I was young.

For future reference, I listed a few examples of the repeaters nearby and near friends and family.

Source: EchoLink.org

USA
K5AMM-R Fort Worth  441.675 MHz 110.9 Hz Node 463758
KM5HT-R Hurst ARC w5hrc.org 442.850 MHz 110.9 Hz Node 549691
WA5CKF-R Irving 146.720 MHz 110.9 Hz Node 634042
WD5RP-L Arlington, TX 145.560 MHz no tone Node 215788
NB7C-L Boise, ID 902.112 MHz Node 93417
N6MEF-R Santa Clara, CA Node 799194 927.838 MHz 100.0 Hz
KA6TGI-R San Francisco bay Node 68042 144.000 MHz 67.0 Hz
K7LER-R West Seattle Node 4515 441.800 MHz 141.3 MHz
K7RPT-R PORTLAND OR Node 758452 147.380 MHz 100.0 Hz

Canada
VA3UN-L Newmarket, ON Node 87273 
442.600 MHZ103.5 Hz
VE3RAK-R Toronto Ont Node 12068 444.700 MHz 103.5 Hz