When families pack for a long trip overseas, they confront the issue of staying in touch with those back home.

Traveling families preparing for an international getaway will grapple with two practical issues they'd rather leave behind — money (whether to carry and use traveler's checks, credit cards, cash or an ATM) and how to stay in touch. The latter challenge is examined here.

There are several options for telecommunications in a foreign country. If you don't need (or want) an easy way for people at home to reach you, and don't mind not having a cellular phone, buy a local phone card. If you want to carry a cell phone with you, for whatever reason, your options will depend on a number of factors, especially the volume of calls you expect to make. The decision is complicated by the various technologies, so stick with me and we'll work through the learning curve together.

GSM & CDMA Standards

Let's define the key vocabulary straight away. Throughout the world, there are several different wireless operating standards—GSM, CDMA, TDMA, IDEN, AMPS. Only the first two will affect most cell phone customers in the U.S.

The GSM standard is used in more countries (currently numbering 205) than the CDMA standard. Within the GSM standard, there are four operating frequencies, comparable to FM station frequencies. The most common GSM phones are dual-band and will have frequencies working internationally (900MHz and 1800 MHz) and in the U.S. (850 MHz and 1900 MHz).

Make sure that your phone has the required bands for international travel. T-Mobile and ATT/Cingular operate under the GSM standard and will work in most GSM countries.Verizon and Sprint are now offering a few phones with GSM capabilities, under the "global phone" banner (However, they are currently somewhat expensive, as are their roaming rates).Only Japan and South Korea are strictly CDMA and a T-Mobile or ATT/ Cingular phone will not work there). If you are buying for international travel, you should purchase either a tri-band 900/1800/1900 or quad-band 850/900/1800/1900.

Other U.S. wireless operators (Verizon, Sprint) primarily use the CDMA standard, which is in use in a few other countries and on most cruise ships. In these CDMA situations, your own CDMA phone will probably work, though at roaming rates which can be costly ($.69-2.49).. These CDMA compliant countries include USA, Canada, Mexico, China, Israel, New Zealand, Thailand, and many Caribbean countries. Check with your wireless provider for a full list. (These countries also have GSM networks) A CDMA phone will not work in a GSM country.

SIM Cards

All GSM phones (but not CDMA models) have a removable SIM (Standard Information Module or Subscriber Identity Module) card inside, which is about the size of a postage stamp and usually found under the battery. These SIM cards interact with the wireless systems available to the phone. There are several kinds of SIM cards which can work with your GSM phone, but the U.S. wireless carriers sell their phone in a 'locked" mode, which restricts usage to their proprietary SIM cards and service. There is a solution, however.

Both T-Mobile and ATT/Cingular (but not yet Verizon and Sprint) will provide unlock codes on request, freeing you to use any SIM card. There are several varieties available that provide cheaper service than available with the original proprietary card--country-specific cards for service in individual countries or "roaming" (a.k.a "global") cards that work in multiple countries. Both kinds of cards offer free incoming calls and text messages in most countries, a significant savings over the carrier proprietary cards.

With the country cards, your phone is a "local" phone, with a phone number of that country. With a roaming card, you dial the destination number, then receive a call back, which, when answered, connects ,to the number. It's a slightly odd system, but it works. Your cell phone number will be based in a European country (U.K., Estonia, etc.). The cost saving is well worth any hassle. Note that a pre-paid SIM card can cost around $60, but may only have $10 worth of airtime. You will need to recharge the card as it runs low, either with pre-paid recharges, by buying the recharge locally in your country, or with roaming cards, by credit card.

Roaming card rates may well be your best bet and can be cheaper than local SIM card rates (as low as $.29/min for outgoing calls locally and to the US) so, in some countries are a better deal (e.g., France) than the local SIM cards.
If you bought an UK SIM card, your local calls would be $.26/minute and calls to the U.S. would be $.09/minute. That's a better deal than the roaming card, but the cards do not work outside the U.K. With a global/roaming card you could pay $.29-.49/minute, for either local or international calls, plus a surcharge of $.25/call, and if calling a European cell phone, an additional $.35/minute. In France, the local rate is roughly $.47/minute vs. the U.S., $.84/minute. Roaming card rates are the same as in the UK.

Country-specific cards, as well as roaming cards, can also be purchased from the U. S. based Telestial (800/707-0031) before you go, saving you the hassle of dealing with it when you arrive. For example, if you do not speak French you may face a difficult task in acquiring a local SIM due to language issues, finding a store, etc. Note that many local SIM cards must be used every two months or so or you will lose the value embedded in the card. Some expire completely after a number of months, some up to 12-months. If bought well before your trip, both varieties of SIM cards provide with you a telephone number before you leave. This is a comfort to both you and your families at home.

Let's examine the most commonly available telephone choices: buy a stored-value phone card; use your own cell phone; rent a GSM cell phone; buy a global callback phone service; rent a satellite phone; or use the hotel phone. Don't even think about the hotel phone. The costs are extreme; think US$10 per minute.

Buying A Phone Card

This is the simplest, cheapest option, but requires that you call from either pay phones or landlines. You will be mobile but cell phoneless abroad. The rates are low and cards are widely available at newsstands, cafes and phone stores.

You can buy these stored-value phone cards (not to be confused with SIM cards) in most countries (including the U.S.). These require you to dial a toll-free number and enter a code from the card followed by the number you're calling or, in higher tech phones, insert the card in the pay phone where it acts like a debit card. In European countries, phone cards are the cheapest option. Be aware that they are country-specific and don't cross borders. Start with €5 or €10 cards. You'll be surprised at how long they last. However, you may find some compatibility problems where certain kinds of pay phones don't accept your kind of card.

The other downside is that friends or family cannot easily reach you. If you don't have extensive calling needs, stick with this. If you want to be easily reachable and/or will make lots of calls, consider one of the following cell phone options.

Using Your Own Cellphone

Your ability to use your own phone depends on the wireless service you currently have, the kind of phone you own, and the wireless standards in the country you're visiting. If you have T-Mobile or ATT/Cingular -- this includes you iPhone owners -- your phone is capable of working in Europe and other countries with GSM service. Call your wireless carrier to confirm the international service before you leave the U.S. With ATT/Cingular, you can opt to pay a $3.99/month charge for discounted rates on international service, either from your home or from a cell phone abroad. It's worth the premium, as the discount is substantial.

Your service should work well in most GSM countries, but the convenience comes at a price. The cost per minute will be at least $.99/minute. And you will also be billed for incoming calls, an expense that can be avoided through other options described below, Text messages will cost between $.35-.50/message.

Currently, using your own phone or Blackberry/Treo/etc. and SIM card is the only way to maintain your data (email/internet/IM) service. T-Mobile, Verizon, and ATT/Cingular offer unlimited foreign data service for $65-70/month with an appropriate phone.. If you need this kind of service, you'll definitely want to go this way. Telestial will offer data plans with its SIM card early in 2008. Confer with your carrier and with Telestial.

Unless you buy the unlimited data plan, beware the IM impulse. Unlike text messages, IM messages and e-mail, and internet browing are "data" and are billed at kilobyte rates. Our son mistakenly thought that his IM sessions were free with T-Mobile during his summer Spanish program on the Costa del Sol. The bills for five weeks were well over $1000, and our endless arguments with T-Mobile brought no relief. It's a disaster you can and should avoid.

If you contemplate substantial phone usage, you will save a significant amount of money by unlocking your GSM phone and using either country-specific local SIM cards or a roaming SIM card. Country-specific cards can also be purchased in your destination country. It will be slightly cheaper there, but will require a bit more work on your part. Again, with this option, your Blackberry email/internet functions will not work.

If you are a Verizon or Sprint user, you're out of luck in GSM countries, unless you've bought one of their newer multi-band phones with GSM capability.. For CDMA countries, check with you provider to make sure that the service is functional in your destination country and to confirm the current rates.

Renting A GSM Cell Phone

If you don't have a GSM phone, only travel to Europe infrequently, don't plan on being there very long and won't be making a lot of international calls but want to be easily reached, the cheapest solution may be to rent a phone. The various providers will ship the phone, for a fee. You'll then know your number before you go.

Among the rental companies is Travel Cell, which provides either single-country service or multiple destination service. The Travel Cell weekly rental is $29.99; insurance is $.99/day. For a trip to France: outgoing local calls $.89/minute; calls to the U.S. or Canada $1.39; calls to all other countries, $4.99, incoming calls are free. If you take this phone to other countries, roaming rates are $4.99/minute. For a trip to the U.K., a rental phone for that country will have significantly cheaper rates. For multi-country usage service, you lose the free ride on incoming calls. Contact Travel Cell at 877/235-5746 for the options and current prices.

Mobal charges $7/day. In France incoming calls are free; calls within France, $1.25/min; to the US, $1.50/minute. Check their website for specific country charges. Roadpost has perhaps the best rates: $49/month for phone rental; incoming calls free; per minute rates ranging from $1.49 down to $.92, depending on the volume of calls made, more being cheaper. Verizon offers rental phones, as well, for $3.99 per day, but rates run $1.49/minute incoming or outgoing. A new player has come into the rental market, Call-In-Europe which offer rentals for $2.99/day, with decent calling rates. They will ship the phone to you in the U.S.

Buying A Cell Phone

If you don't own a GSM phone that can be unlocked and plan on traveling to Europe more than once, going for a multi-week trip, or will require heavy phone usage while abroad, the most sensible plan is to buy an unlocked GSM tri-band or quad-band phone (with proper frequencies). You would package that with either a country-specific or a multi-country roaming SIM card.

This option would provide you with a permanent, easily activated international set-up. My wife thinks I'm a gear nut (and I am), but I found this to be a very sensible option for people who meet these criteria. I had a good experience using one of these phones, even lent it to my in-laws for their trip to Europe, and will use it on our next trip.

There are several companies offering packages of phones and SIM cards, but I found that the most user-friendly, best-value company is Telestial ( 800/707-0031; from outside the US: 858/274-2686). Others include Cellular Abroad, Mobal and Ekit. Compare their plans and rates. Make sure you get a tri-band or quad-broad phone with proper frequencies for your needs.

Here's how it works with Telestial. An unlocked GSM phone will cost you $99 and up. I would advise a very basic phone, like the Siemens A75, which was my choice. You then purchase a pre-paid SIM card. If you are only going to one country, the single-country cards may offer the best per minute rates, (Warning: this type of card may not work in other countries and will incur high roaming rates if it does). These country SIM cards can be recharged in the country by buying recharge cards at newsstands, tabac shops, and phone stores in the host country. You scratch the card to reveal the code and call a number, punch in that code and your account is recharged.

Often the better value and definitely the choice for a multi-country trip is one of several varieties of roaming SIM card options. There are also package deals available which offer a package price for both phone and SIM card. You should explore the choices with a Telestial sales agent and figure out which is the best for you.

Roaming cards are funded with a credit card that can be configured to automatically recharge when your account balance drops below a set number. Then, you'll never run out of phone time and can monitor and manage the account online.

After receiving the phone and SIM card, you insert the tiny card in the phone and follow activation instructions. I have used the Telestial Passport card, and once activated, it worked like a charm. (We did have some initial setup problems, which now seem to have been fixed.) You should confirm with Telestial and other companies that their service works in the countries you are going to.

Global Callback Service

If you are using a country SIM card, there is a nifty little service that will save on calls to the U.S. It's called, Global Callback, from Global Phone. From your cell phone, you dial one of several 'trigger" numbers in the country you're in, allow it to ring only once, then hang up before a charge is incurred. Global Callback then neatly recognizes your number and calls you back with a connection to the U.S. You then dial the number and you're connected. The call that would be $.84/minute on a French SIM card will cost $.30/minute. The charge is billed to the credit card account you set up when establishing the service.

Note that the service does not work with a roaming card, only local SIM cards. This would not be cost effective with your U.S. phone service, however, as you would be paying for incoming call time, plus the callback fees. Global Phone has a range of other products that merit perusal.

Satellite Phones

For the really committed telecommunications warrior needing service in remote areas of the world, satellite phones are an option, but at a price. You can make and receive calls all over the world, including the Poles and oceans. These phones depend on direct line of sight to a satellite, and work best outside without obstruction. They will not work in a moving car. They could be a cost-effective option for cruise ships (where onboard phone rates can be prohibitive), but do your homework and compare the options.

Travel Cell rents units for $149.99 per week, with outgoing rates of $2.49/minute. Incoming calls are free. Telestial rents an Iridium model for $9/day, with outgoing calls at $1.69/minute, incoming calls free, incoming text messages free. You can also buy a Satellite phone at prices ranging from $650-1500. Not for everyone.

Conclusion: There are sensible options, but you will have to do the homework, analyze your calling volume needs, then compute which option makes works best for the geography of your travels. If you're smart, there are serious savings available. After all, who doesn't want to stay in touch at the best price? Skype savvy folks might want to consider this option, but, as they say, that's another story.