TeleCollect Call Conferncing

Note: Parsing of international phone numbers is quite strict.
Please use the following format: +1-123-456-7890.
US Domestic numbers can be entered as 123-456-7890 or 1-602-555-1212
Do NOT use the US escape prefix 011.
Here are some fun numbers to try:

+442074999000 # US Embassy London
+610395265900 # Australia Embassy FAILS
+49-30-8305-0 # Germany Embassy
+61 02 6214-5600 # Canberra Embassy FAILS
+6325301-2000 # Manila Embassy