The fact is that as the connection to the service "national roaming" and her trip is directly related to the number of funds on your personal account. If the amount of funds remaining in the account will be not less than 600 rubles, you will be able to communicate outside the home network at special prices. As soon as cash will be less than three hundred rubles, then roaming will be automatically deactivated and you will not be able to make and receive calls. This rule will apply to those subscribers who use prepaid billing system. For the postpaid system roaming is valid without restrictions (like only the party will be in the home network, the service will be deactivated automatically).
Service with exactly the same name and is available to subscribers of the operator "MegaFon". It also allows you to communicate freely outside the home region. Disconnects and connects the "national roaming" is absolutely free, however, any of these procedures can not be done independently. For this you will need to contact the nearest customer service center or the salon "Megaphone". Activation/deactivation will not take you much time, but will require a passport and the contract on rendering of communication services.
Another Russian operator, MTS, has the opportunity to be in roaming due to the service called "World without borders". For its connection it is enough to dial only one USSD command *111*33*7# and press the call button. In front of you on the phone will appear of the user who will need to follow. Moreover, for service management there is a special self-service "Internet Assistant". Through it it is possible not only to connect different services and to disable them (including the "World without borders"). This system you can easily find on the official website of the company.