By Tim Hasson and Dan Piltch, Marine Computer Systems, Inc.
We'll present an overview of a wide variety of products and services available to cruisers. Much of what we cover is based on our real-world experience helping to outfit our clients with appropriate technology. Since there might seem to be a bewildering variety of solutions, consider how you want to stay in touch before investing in a product. Let your needs drive the technology, don't let an exciting technology seduce you into buying more than you need.
Email appliances range in price from around $100 to $200 dollars, with service plans running anywhere from $10 to $15 per month - which certainly makes them attractive from a cost perspective. While the companies provide stateside local numbers or 800 number access to the system (Earthlink charges a premium for 800# access), outside the country you'll likely be placing an international long-distance call to dial up the mail server. A long-distance calling card from one of the international phone service providers can take some of the sting out of this.
These devices are easy to use and affordable. But unless cell coverage is available, they generally mean tracking down a (hopefully working) pay phone to make your call. Unless used with a satellite phone, they won't work offshore - and there are better ways to do email with a sat-phone, as we'll discuss below. These kind of devices also won't send or receive attachments. Drawbacks aside, our experience with people who have these devices is that they are satisfied with them, and the general comment we hear is that "it does pretty much what I expect it to do".
The first thing to note about cellular phone service is that no cell network was designed with the interests of mariners in mind. Still, if you'll spend a good portion of your time cruising coastally then cellular can be a viable option for at least much of the time.
Here in the US there are two competing cellular technologies in widespread use, CDMA and GSM. Of the two, GSM is more of a worldwide standard. Companies like Sprint and Verizon built their networks using CDMA, while companies like AT&T, Cingular and T-Mobile now use the more worldly GSM. Older standards that used to be common, like the original analog system (AMPS) and AT&T's TDMA, are being shoved aside in favor of more efficient technologies. Right now, all the big cellular networks are in the process of migrating to up and coming "third generation" (3G) technology, which includes high-speed data as part of the service.
This means it's now possible to connect your cell phone to a computer and use it as a modem to retrieve email and browse the Internet. Presently most carriers are offering interim (2.5G) services, which deliver speeds about the same as a home dialup connection. In the Verizon and Sprint world (CDMA) this technology carries the tongue-twisting label CDMA2000/1XRTT. AT&T and others (GSM) use something called GSM/GPRS or an even faster technology referred to as EDGE.
The data service is usually an "add-on" option to your regular cellular voice calling plan. In addition to a capable phone and your computer, you'll typically need a "data kit" consisting of a cable to hook the phone to your PC and some software to manage the connection to the data network. These plans are usually based on how much data you transfer over the network, as opposed to how long you stay connected. Prices vary by carrier, but start at around $10/month for low-volume users and range on up to $100/month for high-volume business users.
If you spend a lot of time in areas where cell coverage is available and would like to have email in addition to voice, it may be worth a call to your wireless carrier to get more specifics on these new data services.
Another nice development on the cellular front over the past year has been the introduction of new international calling plans and "world phones". While "world" might be a little optimistic, many carriers now offer an international option which will let you pack the phone you use here in the US along with you when travelling overseas, and make calls at a flat per-minute rate. The per-minute rate varies by country from around $1 to $5, and you may need to upgrade to a latest-generation GSM phone to participate in the international service. This again is a "varies by carrier" subject, so check with your cell phone provider for details on what options are available to you. But the bottom line is that the whole international roaming scenario has recently become a lot easier and more manageable than it used to be.
One final note on cellular - adding an external antenna (around $150) and a cellular amplifier or "power booster" (around $300) will almost certainly help extend your coverage, especially offshore and in weak signal areas. Your neighborhood cell phone store will likely carry these items and be able to get you hooked up. But bear in mind that no matter how much you boost your signal no cellular provider has perfect coverage everywhere, and you will likely encounter some blackout regions along the way. It's still just a cell phone.
Marine Single Sideband
Consider "ship-to-shore" radiotelephone service, the ability to call a shoreside operator via SSB and "patch in" to the telephone network and place a call. This kind of service was commonplace not too long ago, and is still offered by a handful of stations around the globe including Bern Radio in Switzerland, Australia's Penta Comstat organization, Radio Monaco and others. AT&T's "High Seas Operator" service ceased in 1999, and the only remaining US-based radiotelephone provider is the network organized around coast station WLO near Mobile, Alabama.
WLO changed hands about a year ago, and is now operated by radio veteran Rene Steigler and a company called ShipCom LLC. WLO used to go off the air late at night, but since taking over the station the folks at ShipCom have extended the hours of operation to 24/7. For those in the Pacific, WLO's sister station KLB has been reactivated and is back on the air, operated by remote control from Mobile. KLB is near Seattle and another station, KNN near Los Angeles, can be brought up on an as-needed basis. In addition to voice phone calls, the ShipCom stations broadcast weather forecasts for the Atlantic, Gulf of Mexico and Pacific as a public service. They also offer Email capability (WLO only), and provide a variety of other services, mostly of interest to commercial shipping. A prearranged account is preferred for the telephone service, with rates starting at around $4/minute for US domestic calls. Perhaps best of all, the experienced and friendly operators at WLO are standing by and listening around the clock, and have a tradition of assisting vessels in distress that goes back more than fifty years.
Being able to place a phone call is nice, but SSB has more benefits for the cruiser which are likely to be used on a daily basis. Not the least of these is the pure social value of staying in touch with fellow cruisers, whether directly or via one of the many cruising "nets" which operate in many regions. Herb Hilgenberg's Southbound II weather net is legendary among East Coast and Caribbean cruisers. Others operate for more general purposes, such as the daily Cruiseheimer's Net. All are great ways of staying in contact, finding new or old friends and keeping up with the latest news.
There's also a wealth of weather and safety information available on SSB. Voice weather forecasts, text forecasts sent using radiotelex or radioteletype and weatherfax charts are broadcast by stations around the world and are free for the taking. Text and fax used to require dedicated devices to receive and decode the signals. Nowadays some simple software on your personal computer can do the job, using nothing more than a cable from the computer's sound card to the SSB's headphone jack.
It's certainly true that SSB communications are subject to the whims of propagation, and the sheer number of buttons, knobs and switches on the gear can be intimidating to some at first. But in a similar sense, on your first time aboard a sailboat the wind and all those wires and ropes were probably baffling, too. Some training, perhaps from a knowledgeable friend or your vendor, and plenty of hands-on experience will unravel much of the mystery.
It's also true that reliable SSB operation depends a lot on a good installation, especially with respect to the antenna grounding system. SSB installation issues are the subject of a lot of conflicting information and opinions, and we won't add to the fracas here. If you're not already a "radio head", the best bet is probably to find a competent installer you trust and hold him/her to a performance standard.
Over the years, literally dozens of standards or protocols have been developed to send text and digital information over the airwaves. The standard that's evolved as the de facto one for SSB Email providers is something called Pactor, invented by a group of German amateur radio operators in the late 1980's. The name is actually something of a tecchie double-entendre. On the one hand it's an acronym, short for PACket Text Over Radio. But Pactor also translates in Latin as "one who arranges contracts, a negotiator" (think "making a pact"). This is actually a clever reference to the sophisticated methods the Pactor protocol uses to set up, and then maintain, a radio data connection.
So strictly speaking, Pactor is a protocol, or language, for transmitting digital information via radio. The interface box that connects to your SSB and speaks this language over the airwaves is a radio modem (sometimes called a terminal node controller). Modems manufactured by the group who invented Pactor are called PTC's, short for Pactor Terminal Controller, but most of us just call them "Pactor modems".
The German engineers who developed Pactor formed a company, Specialized Communications Systems (SCS), to refine and improve the protocol as well as manufacture their own line of Pactor modems. A faster protocol, Pactor-II, was introduced in 1994. Pactor-III, the latest version and fastest to date, came along late in 2001. Both Pactor-II and Pactor-III are proprietary protocols, available only in the PTC boxes manufactured by SCS. The company introduced a new upgrade to their family of modems last summer, dubbed the PTC-IIEX. While the improvements are pretty much invisible to the user, the IIEX has a faster processor and more internal memory. It retails for $699.
We need to point out that Pactor-III is a new protocol, not a new box. The Pactor-III standard can be installed as a software upgrade to most existing PTC's, or can be added as an option to new modems for a license fee of $150. In addition to being three to five times faster than Pactor-II, Pactor-III does an even better job of keeping a radio connection going, even under tough signal conditions.
Another thing that needs to be considered with regard to SSB Email is the radio itself. Digital modes like Pactor work an SSB transceiver pretty hard, especially when first calling another station. The Pactor protocol is also somewhat sensitive to transceiver switching time (the time it takes the radio to toggle from transmit to receive, usually measured in milliseconds). Newer SSB transceivers such as the Icom M802 and Furuno FS1503EM were designed with the demands of Email in mind, and should give reliable service.
With a computer, Pactor modem and suitable SSB transceiver at hand, the next question becomes "who to call?". Just as you need a service provider like AOL or Earthlink to access the Internet from home, you'll need an arrangement with someone to provide the radio link and a shoreside connection to the Internet while at sea. SSB Email providers generally break in to three categories; the volunteers (Winlink 2000, SailMail), the regional operators (CruiseEmail, MarineNet, ShipCom), and the large commercial operators (Globe Wireless, SeaWave Digital).
Perhaps surprisingly, the largest and busiest of these is likely the volunteer Winlink system. Developed and managed entirely by a global network of amateur radio operators, Winlink has 39 shoreside stations, called PMBO's, operating worldwide. Almost all of these stations support the faster Pactor-III protocol mentioned above. Some 4,400 users exchange around 155,000 email messages per month via Winlink, and the numbers are increasing steadily. Beyond Email, the Winlink system offers numerous features including access to a wealth of weather information and several ways to file position reports, which friends and family back home can view in almost real time via the Internet. The service, including the software which runs on your onboard computer, is offered as a public service and is entirely free, but there are limitations. Winlink operates on the amateur ("ham") radio bands, and access to the system requires at least a General-class amateur radio license. There are also restrictions on the conduct of business via amateur radio, so this may not be the best option for users who need, say, to manage business affairs via email.
If you can't picture yourself taking the amateur radio route, another option is the non-profit SailMail Association. Sailmail takes a "club" approach, charging it's members annual dues to access their network of 14 private coast stations around the globe. The organization is set up expressly to meet the needs of private cruising boats, and dues are a very reasonable $200/year. Sailmail offers text email, but does have limitations on attachments. In an effort to give all members equal access to the system, SailMail also limits connect time to an average of ten minutes per day, which is enough to exchange a few casual email messages. All the SailMail stations support Pactor-III, to help members make the most of this limited connect time. An affiliated service called SailDocs gives good access to text weather forecasts. Unlike amateur radio, there are no limitations on the conduct of business via SailMail, but high-volume users would probably be better served by one of the commercial providers.
Systems such as CruiseEmail, MarineNet and ShipCom are commercial operators who generally serve more focused regional areas such as the US East Coast and Caribbean (CruiseEmail, MarineNet) or the Gulf and Caribbean (ShipCom). To extend coverage, often these companies maintain reciprocal "roaming" arrangements with other regional operators overseas such as the Radiomarine Network in the Philippines or Kiel Radio in Germany. Commercial operators generally support email attachments and have no restrictions on the conduct of business affairs or daily connect-time limits. Depending on the provider, they may offer other value-added services like access to weather information as well. Subscription charges are typically in the range of $200-$300 per year.
While their services are really geared towards fleets of large ships, enterprise-solution providers like Globe Wireless and SeaWave Digital continue to maintain global SSB radio networks as a complement to the satellite-service offerings at the core of their business. For example, Globe Wireless operates over twenty SSB stations worldwide, including some of the legacy radio stations from the "glory days" of maritime radio. But the service they provide via these stations doesn't really have anything to offer those of us in the cruising community, so Globe is pretty much "off the radar screen" in terms of SSB email.
SeaWave Digital, on the other hand, will still welcome recreational vessels and private yachts as clients. In fact, SeaWave has implemented one of the more interesting advances in SSB email technology to come along in a long time. It's called Automatic Link Establishment, or ALE, and it works like this: during idle periods the software on your computer and your radio work together to scan the many frequencies used by the SeaWave coast stations. They do this repeatedly, and the software compares the quality of the signal it hears from different stations on different frequencies to decide which location and channel combination would be best for communication at any given moment. The idea is that when you sit down to send an email, the software already "knows" how to make the best possible radio connection to transmit your message, which eliminates a lot of channel-switching "trial and error".
ALE has been around for years, implemented mainly by government and military users. This is the first commercial marine application of the technology we're aware of, and the idea of reducing SSB email to sat-phone simplicity is intriguing. The SeaWave Navigator 2.0 system, which includes a modified Pactor modem compatible with the proprietary SeaWave network, is listed at $1,500.
It took thirty years, but Clarke's vision was realized in April of 1965. That's when INTELSAT-1, aka "Early Bird" ,was launched as the world's first commercial communications satellite with the job of providing a reliable 24/7 link between Europe and North America. Today there are thousands of satellites orbiting the planet being used for weather observation, navigation, and of course, communications.
It takes some power and a pretty good aim to get a radio signal to bounce off a little target over 22,000 miles up in the sky, so the Inmarsat equipment certified for marine use is generally fixed-mounted, as opposed to handheld options available from other providers. A typical Inmarsat setup consists of a terminal device mounted below decks (usually near the chart table), and an external antenna above deck. Antenna sizes, for the types of equipment that can be fitted on most cruising boats, range from about the size of a large grapefruit to almost three feet across.
With almost 25 years of experience, and having launched several generations of satellites, Inmarsat's service offerings are highly regarded, extremely reliable and (some feel) a tad expensive. Inmarsat offers a range of solutions which include voice, facsimile and data at speeds ranging from 600 bps to 64,000 bps. Inmarsat's "4th-Generation" satellites, slated to become operational in 2005, promise to offer data speeds up to 432,000 bps (practically equal to a home cable modem or DSL connection).
One of their more interesting offerings is the Inmarsat-C service, which is first and foremost a safety and distress system. Inmarsat-C (Sat-C) equipment consists of a terminal about the size of a car radio with just one simple red button. This box also gets connected to a dedicated display unit or a personal computer. The Sat-C antenna is on the smaller side, roughly grapefruit-sized, and the antenna/terminal combo also has a built-in GPS unit.
When the terminal is turned on, the equipment automatically receives daily bulletins containing weather forecasts, navigation warnings and other marine safety information. These bulletins, which are free of charge worldwide, are from a service called SafetyNet which is one piece of the Global Maritime Distress and Safety System (GMDSS). The terminal "knows where it is", thanks to the built-in GPS, and only downloads bulletins appropriate for the waters in which the vessel is operating. So, for example, a boat cruising to Newfoundland won't even be bothered with warnings about a typhoon brewing deep in the South Pacific.
In a distress situation, a press of the red button on the Sat-C terminal automatically transmits an alert along with details about the vessel and it's position to the Rescue Coordination Center (RCC) responsible for the waters in which the boat is sailing. The RCC and the boat in trouble can then quickly establish a two-way text messaging session with each other to clarify the nature of the emergency or coordinate rescue details.
Inmarsat-C is essentially a mobile packet data service, although it only moves data at a pokey 600 bps. Some service providers do offer simple text-only Email as an option via Sat-C, typically priced at just under a penny per character (spaces count).
When you consider the text-only limitation (no attachments) and relatively high cost compared to other solutions on the market, it's hard to justify Inmarsat-C as a primary Email solution. However as a text paging system or emergency backup it is extremely reliable. And as a distress and safety system, it's a proven lifesaver. Inmarsat-C terminals are available for around $3,600. The SafetyNet marine safety bulletins and distress-calling features are free, and there is no monthly fee regardless of whether you use the terminal to send Email or not.
While Sat-C is text-based only, Inmarsat's mini-M service is a more mainstream communications tool. Mini-M does voice, fax and data in one multi-purpose terminal about the size of a laptop computer, with a handset that looks like a conventional telephone. The antenna used for mini-M is about the size of a basketball.
Mini-M looks like a conventional telephone, and it pretty much works like one as well. Dialup data connections can be made at 2,400 bps, a speed which may be increased for some tasks using compression software (see sidebar). Pricing varies a little by service provider, but typically runs in the range of $2.00 to $3.00 per minute depending on where and when you are calling. Most providers have no monthly fee, and you pay only for airtime used. Incoming calls are paid for by the caller, who is making an international, long-distance telephone call at a rate determined by their long-distance carrier. Prices for the terminal equipment start at about $4,700. Mini-M uses Inmarsat's more selective "spotbeam" coverage and there are some gaps, most notably in southern ocean regions.
Mini-M enjoys a reputation as a steadfast and reliable service, but is getting harder to cost-justify against newer competing services like Iridium that offer more complete coverage, lower equipment costs, and lower per-minute calling plans.
Finally, there's the new Fleet family of terminals. Fleet is an interim service designed to bridge the gap until Inmarsat's new high-speed satellites go in to orbit beginning next year. Some Fleet terminal equipment is supposed to be compatible with the new satellite constellation when it becomes operational.
There are actually three kinds of Fleet terminals; F77, F55 and F33. As you might guess "F" is for "Fleet", and the number following indicates the approximate size, in centimeters, of the equipment's antenna. For example, Fleet F55 equipment uses an antenna that measures about 55 cm, or 21" . Actual antenna sizes vary a bit from this depending on the equipment manufacturer, but those are the general ranges.
Fleet is intended as a total communications solution, with voice, fax, and two kinds of data service. There's a dialup-type connection which operates at speeds up to 64,000 bps (F55 & F77 only) for transferring large files or similar heavy-duty tasks. This high-speed connection is "on demand", in the sense that it only kicks in when you ask for it, and carries a premium airtime pricetag of around $8 per minute. For light-duty activities, say checking email or instant-messaging with the office back home, Fleet also has an "always on" data connection called MPDS. MPDS is short for Mobile Packet Data Service, and is billed based on the amount of traffic you move over the network as opposed to airtime.
With an antenna almost three feet across, F77's large size means it's likely suited only to larger vessels. More appropriate for us, F55 terminal equipment (26" dome) is available with terminals costing in the $15,0000 - $20,000 range. Voice calls will set you back anywhere from $2.75 - $3.50/minute and the MPDS data connection runs around $4.50 per megabit.
F33 equipment is just coming on the market as this is written, with terminals priced in the $8,000 - $10,000 range. With a 13" dome, F33 can be set up even on smaller boats, but the tradeoff is that the dialup "high-speed" data connection is limited to 9,600 bps. Like the speed, airtime costs for this type of connection will be significantly less than F55. On the other hand, voice and MPDS pricing will likely be about the same.
Inmarsat has more offerings, but they are mostly of interest to large commercial vessels or other industries, such as aviation. And in recent years we've also seen some new players take to the satellite communications field, offering services as an alternative to those available from Inmarsat.
After a fitful start that's been well-documented, the operation is now owned by a privately held company, Virginia-based Iridium Satellite LLC. Iridium Satellite recently announced that the company is now operating beyond the break-even point and is at a cash flow-positive status.
Iridium is unique in that it uses a scheme called inter-satellite links to route both voice and data calls from anywhere on the planet to a satellite that's in view of just one gateway station in Arizona. From this gateway, calls are routed over the land-based communications network. Because the satellites are in a low earth orbit they can be reached with less powerful equipment, including handheld devices.
Like mini-M, Iridium's native data rate is a somewhat slow 2,400 bps, though this throughput may be improved with compression techniques. Voice quality can suffer a bit from all the hopping from satellite to satellite, but is within tolerable levels for most. One neat feature we've put to good use is Iridium's Short Messaging Service, or SMS. This lets anyone with access to email send a brief text message (up to 160 characters) that will be displayed right on the screen of a recipient's Iridium phone. Going in this direction, SMS text messaging is free. Last summer, the company introduced the ability for users to send an outbound SMS message from their Iridium handset, although this feature is limited to certain models of equipment of newer vintage. There is a small fee for using this SMS feature.
Priced at just under $1,500, Iridium's handheld phone is about the size and weight of a standard home telephone handset. This works well on deck or while you're out and about, but will probably not work indoors or below deck. Fixed-mount units are available starting at around $2,700, but sacrifice portability. For the best of both worlds consider a cradle mount, similar to a car kit for a cell phone, which will let you mount a handheld phone securely down below and use an external antenna while underway, then remove the phone and carry it with you on shoreside excursions.
Iridium's service rates actually went up last year. While there's some variation depending on who you contract with for service, figure on about $30/month for a service plan with per-minute rates of around $1.50. If you think you'll use the airtime, it may be possible to do an end-run around the monthly fee (and in some cases any account activation fee) by purchasing pre-paid blocks of airtime minutes. Be sure to ask your dealer about this.
Globalstar filed for bankruptcy and started taking steps to reorganize its finances in February 2002. Since then a couple of deals to bail out the company have been proposed, all of which fell apart at the last minute. While all this was going on, key Globalstar investor Loral Space Communications also filed reorganization paperwork last summer. As this is written (November 2003) a promising plan is afloat to raise capital by selling a majority interest in Globalstar to a new investor. It looks like this saga will end on a good note.
While Globalstar's had it's share of financial worries the network has never gone "off the air". There have been regional outages however, including a pesky one which occurred in the middle of the Caribbean 1500 Rally last fall and lasted for several days. Those troubles were reportedly due to a problem with Globalstar's Caribbean gateway station in Puerto Rico.
To attract more subscribers, Globalstar reduced prices on their equipment and service plans to levels that are very competitive with cellular. Handheld Globalstar phones are street-priced at less than $500, and calling plans range from $35 to $500 per month. Like cellular service, Globalstar calling plans include a "bucket" of airtime minutes in the monthly calling plan, with additional minutes running anywhere from 49 to 99 cents per minute. Roaming and long distance charges can apply when travelling or calling outside of the Globalstar USA "home" service area.
As with Iridium, a permanently installed system with an external antenna works best while underway. Fixed-mount equipment is available starting at around $2,300, or the Globalstar Car Kit can be adapted for marine use to secure a handheld phone down below.
Globalstar also offers SMS, but the service is limited to 19 characters. Globalstar's packet data service works very well, and is available across the continental US, Canada and Caribbean. Outside this area, you can still use the phone as a modem to dial up a third-party service provider for web and email access. The native data rate is four times faster than Iridium or mini-M, at 9,600 bps. Some innovative companies have developed ways to accelerate this even further, using various combinations of hardware and software compression.
An example of this is SeaTel's WaveCall MCM3, which essentially gangs together three Globalstar modems in parallel. When combined with Seatel's compression software, this multi-channel approach achieves web-browsing speeds of 19,200 bps to 144,000 bps. As an added bonus, the phone can be used for a voice call while accessing the Internet at the same time. The MCM3 system is $10,000, about the same as Inmarsat's F33, but the data throughput is faster and airtime is less expensive with this option. However, you are limited to the Globalstar service area.
SkyMate supports plain text email with no attachments. One clever feature will deliver your email as a fax, or as a voice message read by a synthesized voice. This is helpful if you need to send messages to someone who doesn't have an email address, such as an elderly relative perhaps. The system also does position reporting, and the people who receive your reports can click on a web link to view a plot of your location on the web, using a free service from Maptech.
SkyMate also offers access to several good sources of weather information, including NOAA text weather forecasts, selected weatherfax charts, buoy reports, and even NOAA NEXRAD radar imagery. There's also a way to request a semi-custom forecast for your precise location, based on your GPS-plotted possition. An optional vessel monitoring kit provides daily reports on things like your boat's bilge water levels and battery charge state while you're away. This option will email or telephone you with an alert if a problem is detected.
The SkyMate equipment consists of a terminal about the size of a shoebox lid, which gets connected to a personal computer and (optionally) your GPS. The system uses a VHF antenna which can be mounted anywhere on deck with a clear view of the sky.
The SkyMate software which installs on your computer is browser-based, with an Internet "look and feel" that is extremely intuitive and easy to use. The basic SkyMate equipment costs about $800, and volume-based service plans are available ranging from $15 to $70 per month.
Integrated, Multi-path Solutions
The catch is that each of these devices works a little differently ("Do I have to dial 00 with the satellite phone?"), and each requires it's own unique type of connection to your computer system for email ("Has anybody seen the USB cable for the cell phone?"). They also require you to make a decision every time you go to communicate ("Is there cell coverage here? Nope, guess it's sat-phone time."), based on things like coverage availability and what the call is going to cost you.
Companies like Telaurus Communications and SeaWave tie together these multiple communications modes and hide them seamlessly behind just one, simple to use interface. High-end integrated solutions can even be set up to determine what mode to use for different types of communications, using pre-established rules.
One example of this is the NavSeries, another offering from SeaWave. NavSeries combines GPS, an Iridium satellite phone and an (optional) GSM cell phone in one box about the size of a laptop computer, and delivers both voice and data services. The data service offers email, including attachments, along with access to NOAA weather forecasts and a position-reporting feature. SeaWave's Throughput Technology Software is built in to provide compression and streamline connections (see sidebar).
This is multi-path at it's simplest; if the box sees a reliable GSM cellular signal it uses that, otherwise it falls back on the Iridium satellite connection. One big advantage is on the administrative end - individual users can have their own accounts, but all charges get consolidated on one bill that can be broken out by user and itemized, "hotel-style".
As you can see, there are more options than ever before for offshore communications. The choice between email appliances, cell phones, SSB, and satellite can be intimidating. However, don't fret about not being able to choose the single best solution as you'll find that most real-world situations are best dealt with by using a number of different technologies. See the sidebar Three Ways to Stay Connected for examples of what people are really doing on their boats.
Keep in mind that as with most technology decisions, there is no system that fits everybody's needs universally. Each boat will be heading to a different place and each sailor will have different needs for staying in touch (or being intentionally out of touch).