The voltage in Mongolia is 220 V which is the same voltage used in China, Greece, Russia, South Korea, and the United Arab Emirates.
220 V has an advantage over lower voltage such as the 110 V that it is cheaper to transmit. On the other hand, 220 V is more dangerous than lower voltages.
The plugs used in Mongolia are C or E. Moreover you can use a universal plug adapter or converter.
Plugs/sockets are usually an issue when it comes to traveling, so always make sure you travel with a universal plug adapter.
Mongolia GSM Frequency (ies)
Mongolia uses the followig GSM frequencies: GSM 900 / GSM 1800.
When travelling, make sure that your phone supports the GSM frequency of the country you're traveling to. Usually the supported GSM frequencies are printed on the box of your phone as well as its manual.