Disconnecting from technology can be the best part of a trip. Unfortunately, it is not always an option. For business travel, long-term trips and impromptu vacations, you may need a way to keep in touch, both locally and internationally.

This can be expensive, says Caroline Costello, who has written about international mobile use for the travel tips website Independent Traveler. She suggests doing research and calling your mobile phone carrier before leaving town. "Especially if you've never used your phone to travel abroad. Because you're establishing whether you can even use it in another country."

The options for using mobile phones abroad, Costello emphasizes, vary tremendously based on your plan, your carrier, the type of phone you have and the amount of time you spend on your phone. So, we have sorted through some of the cheapest options for cellular use abroad.

Using your own phone abroad
Understanding your phone's technology can help you determine whether to use it abroad. Almost all American phones use either GSM (Global System for Mobile Communications) or CDMA (Code Division Multiple Access) technology. In the US, GSM phones take SIM cards, memory chips that store data including contacts, while CDMA phones do not. Currently, AT&T and T-Mobile offer GSM phones, while the other top cell carriers offer mostly CDMA phones. (TracFone is the exception, offering both.) View GSM worldwide coverage and roaming information here and CDMA's worldwide coverage map here.

If you have a GSM phone, you can convert it to a local phone abroad by buying a local SIM card for it. This is especially useful for making cheap, local calls. However, you can also use this new pay-as-you-go phone to call home. One method is to use international phone cards. Affordable cards can be found at Time Dial, a website that searches multiple price comparison sites. Another option is to use Skype-To-Go. Available in 18 countries, this service works just like a phone card, except it is free for Skype users with a monthly plan or Skype credit. Plus, Skype-To-Go stores up to six speed-dial contacts, so you do not have to keep re-dialling numbers.

If you have a CDMA phone, your best bet is to rent a phone when you get to your destination. (This is discussed in the next section.)

If you have a smart phone, you have potentially cheaper options. Skype has applications for smart phones (including the iPhone, Android and Blackberry) which allow travellers to use Skype through their phones - talking normally into receivers and connecting to Skype contacts. This is 100% free as long as you are within range of a wi-fi hotspot (and have turned off Data Roaming). If you subscribe to Skype or buy as-you-go Skype credit, you can also call mobile phones or landlines.

If you expect many calls while away, it may be worth adding Google Voice to the mix. You can use Google Voice to forward calls to one voice mailbox, which you can check from your smart phone. To do this, set up a Google Voice number before leaving town and forward your home, work and mobile numbers to that number. Then, forward your Google Voice number to your Skype account. The result is all your voicemail messages in one central location.

Whichever way you use your smart phone, do not forget to turn off Data Roaming before leaving your departure city if you want to avoid international data charges. For iPhone users, AT&T has these travel tips.

Renting a phone abroad
You can usually rent a local phone as soon as you land in a new country. Affordable rental phones can be found at most aeroports. For the cheapest options, though, shop around before travelling, advises Costello. She suggests browsing online at TravelCell, TripTel, PhoneRentalUSA and Cellular Abroad, and finding out if your mobile phone carrier has a local store in your destination city.

To call home from your rental phone, phone cards and Skype-To-Go are still great options.

Bringing your laptop instead
Bringing a laptop can cut down on communication costs. Many hostels and hotels offer free wireless internet, as do some coffee shops, libraries and restaurants. Skype is still the best way to use your computer as a phone. Convince the people you call the most to download Skype so you can talk to them for free. Or, pay a small fee to call any mobile phone or landline from Skype.

Leave the electronics at home
Leaving your phone and laptop at home can be liberating. You can focus on travelling without having to worry about either getting stolen. Doing so, though, does not mean you have to fall off the face of the earth. Most towns and cities have extremely inexpensive internet cafes, and most hostels and hotels have at least one computer.

When all else fails, there are always pay phones. If you choose this route, it still pays to be prepared, insists Independent Traveler's Costello. She learned that lesson well when trying to call her mother from a Moroccan pay phone using a phone card whose instructions were in Arabic. "That was a nightmare, trying to figure out that card. It took me days to finally get in touch with my family."

Roaming abroad
If you have to bite the bullet and use your mobile phone abroad, you will incur charges. Here are links to international roaming information for the top four US cell carriers:

Travelwise is a BBC Travel column that goes behind the travel stories to answer common questions, satisfy uncommon curiosities and uncover some of the mystery surrounding travel. If you have a burning travel question, contact Travelwise.