Sometimes it just doesn't work or it only works in one direction.
Steven Fisher use to maintain a user reported list of which networks
work or doesn't work with Fido but that page is gone.  You can check
this thread at Howard Forums for some user reports as well:
http://www.howardforums.com/showthread.php?s=&threadid=291518

PS.  Instead of 011, you can use the + symbol instead.  On GSM phones,
I recommend entering ALL phone numbers like so:
+country_code (rest of number).
for example:  +1 604 1234567
or:  +49 177 1234567

This way, the number will always work no matter where you are.  The
network will know if you are making a long distance call or not.

Either key 011-44-20-[8 digit London number] or +4420[8 digit London
number]  To do a + press the * key quickly twice on Nokia of hold the
0 key on Ericsson and Motorola.
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