Posted by Joseph Reyes in 
Many of today’s cell phone makers and providers rely on a tiny piece of equipment in your phone called a SIM card. SIM stands for System Identity Module. Its purpose is not to store much in the way of data – typical SIM cards have memory capability in the 64-bit range – but to prove to your carrier that your account is behind the phone making the call. SIM cards can be taken out of a user’s phone and put into another compatible telephone without interruption of service.
Portable by Design (But not Necessarily by Nature)
While they are portable in design in this way, there are some companies (AT&T is one of them) that have locking SIM cards that will only work in the phone of manufacturing origin. (There are many websites that can tell you, however reliably, how to cheat your way around that.) That’s one way in which they can be compromised as an open-source device. It is also the case that some carriers may not work overseas, raising the specter of having to purchase phones (often with service agreements) in other countries.
More than One Way to Skin a Cat
Between the hassle and the expense of having to hunt down new communications equipment, a seemingly routine trip can be turned into a bit of a frustrating nightmare, especially in destinations involving language barriers. This can be annoying on a pleasure cruise – and costly if one’s itinerary is printed on company letterhead.
The most practical way around all of these headaches is to purchase ahead of time a temporary SIM card or a sim only contracts. This can also separate your business expenses into an easily-decipherable account. Some plans have a fee schedule based on the amount of time and/or data transferred; others may offer flat rates across the board. In the time-honored tradition of equating time to money, it may make good sense to “rent” a SIM card for overseas travel rather than risking potential snarls.