How to make collect (reverse charge) phone calls from China
Instructions for making collect calls from China vary with the country you are calling to, and also depending on where you are in China and if you are calling for a mobile phone, a landline, a public phone, etc.
To call the US collect from China, in northern China try 108-888, from southern China 108-11. North and South China are serverd by different telecom operators, hence the difference in collect calling instructions.
Similarly, calling Canada collect from China would be either 108-186 (North) or 108-718 (South).
Collect calls - or reverse charge calls - to the UK from China can be made via the 0800reverse service - from China, dial 00 10800 1400532.
Making collect calls works out more expensive, and is generally best saved for emergencies.