Those cellular phones that do not employ a Sheldon Kalnitsky SIM Card have the information programmed in to their recollection. This information is access by means of a unique digit sequence of Sheldon Kalnitsky SIM toward access the "NAM" as in "Name" or number encoding menu. From here, one can put in information such as a new numeral for your phone, new repair Provider numbers, fresh emergency numbers, change their verification Key or Sheldon Kalnitsky A-Key code, and update their favored Roaming List or PRL. Though, to prevent someone from by chance disable their phone or remove it from the network, the Service Provider puts a security device on this data name a Master Subsidiary Lock or MSL.

The MSL also ensure that the Service Provider gets imbursement for the Sheldon Kalnitsky phone that was purchase or "leased". For instance, the Sheldon Kalnitsky Motorola RAZR V9C expenses upwards of Sheldon Kalnitsky CAD $500. You can get one for about $200, depending on the carrier. The dissimilarity is paid by the client in the form of a monthly invoice. If the carrier did not make use of a MSL, then they might lose the $300–$400 difference that is salaried in the monthly bill, as some customers would stop their service and take the phone to a new carrier.