Online Connections:
Acoustic couplers should work when all else has failed

People who have tried them, curse them. They’re seen as bulky, clumsy and decidedly low tech. Yet acoustic couplers are about the only way to ensure that you will be able to absolutely, definitely, without a doubt make a connection with your modem from nearly any phone, in any town, in any country in the world. Acoustic couplers may be universally loathed, but whether you need to send a fax or go online, couplers are a form of insurance that is too attractive to write off out of hand.

Some of you may remember the early ancestors of acoustic couplers, modems with two large rubber cups that operated at blazing speeds of 300 baud or less. You’ll be pleased to know that even though today’s couplers resemble their predecessors somewhat in appearance, there are few other similarities.

First, today’s couplers only couple. They no longer have built-in modems. They must be used in conjunction with your regular laptop modem. Second, couplers are no longer limited to prehistoric transmission speeds. In fact they are quite capable of operating at 24.4 or even 28.8 kbps.

The role of the coupler is to convert audio signals that are traveling over the phone lines to the analog signals that your modem normally encounters when it is connected directly to a phone line. To do this, the acoustic coupler attaches — in a rather inelegant fashion — to the telephone receiver (handset), with one small rubber cup pressing up against the mouthpiece and a second pressing against the ear piece.

This simple technique of pressing the coupler against the telephone receive eliminates many headaches. No more fidgeting with phone line adapter plugs, screw drivers, alligator clips, or digital phone line converters. With couplers you simply put the receiver in place on the two rubber cups, secure firmly in place with the large Velcro band that is attached, and you’re up and computing.

Of course, it’s not all as easy as that. Using a coupler means learning to work around the equipment’s quirks. It means learning a new set of tricks. But in the long run, you may find that acoustic couplers are an efficient and economical way to stay online.

Road test

To test my new acoustic couplers under a variety of circumstances, I decided that I would only use the couplers to go online during a week’s trip to central Europe. I traveled with a SureLink AcoustiCoupler 100 sold by PORT Inc, a computer accessories company in Norwalk, CT, USA. I used it with a 28.8 kbps PCMCIA modem in an IBM ThinkPad. I found the learning curve steep at first, but it didn’t take long to before I achieved quite satisfactory results. Soon I was making connections from phones that I would never have been able to connect from before, including Swiss Pay phones.

Fitting the coupler into place

On the first night of my trip I faced a digital hotel phone system in Luzern, Switzerland. At first I was optimistic, as the phone was connected to the wall with an RJ11 plug, but the IBM Modem Saver alerted me to the higher voltage of the digital line. So I reached for the acoustic couplers.

Somehow the Swiss seem wedded to oversized telephone receivers. The hotel phone receiver was big, and it was shaped rather like the letter ‘J’. To make matters worse, the single, small hole that opened to the microphone was completely off center on the lower part of the ‘J’ that jutted out toward the mouth. I had my doubts, but I adjusted the cups on the coupler to their greatest span and used a little rubber disk that the coupler manufacturer had thrown in to assist in situations like this.

The goal with acoustic couplers is to have the computer signals transmitted loudly and clearly between the paired microphones and speakers of the acoustic coupler and the telephone. Consequently, you need the couplers to fit snuggly against the receiver. I found that I had some small gaps around the phone’s mouth piece, so I reached into my suitcase and found a clean sock, which I used to wrap several times around the mouth piece.

The results were quite successful. I made my connection to a local POP using the iPass roaming Internet access service.

Later in the trip I sought to connect from a residence in France. The one-piece phone was a long, thin bar, but despite it’s odd shape it sat well on the coupler. The only problem was that the cup that fit over the mouthpiece of the phone also covered the button used to hang up the phone.

The dial tone would naturally sound immediately when I took the phone off the wall. It would then take up to a half minute to get the phone seated properly on the couplers, and by that time I wasn’t certain whether I still had the dial tone.

My solution was to disconnect the phone line from the phone (it used a regular RJ11 plug) until I had the phone properly in place. Then, when I was ready to dial, I plugged the phone back in and had my dial tone.

In transit in the Zurich airport, I decided to check my Email once more before boarding my flight back to Boston. I found one of the few coin-operated payphones still found in the airport and used the top of the full set of Swiss phone books as a table on which to open my laptop.

The payphone had clearly been designed by someone from the German side of Switzerland rather than the more style-conscious French or Italian parts. The receiver was heavy, long and wide. But the surface of the ear and mouth pieces were flat and my coupler was able to stretch far enough to make a sound connection.

One bit of advice I’d offer: Have a quick look at the directions before using your couplers. For one thing, on the PORT model there is no indication on the coupler itself which of the two cups should be placed on the receiver’s mouthpiece. Obviously this makes a world of difference. (The larger of the two cups is placed on the receiver’s mouthpiece.)

Dialing your connection
The trick to a successful connection is the ability to monitor the connection process. By keeping track of what’s happening, you’ll be able to adapt what you’re doing to what is actually happening on the phone line. To do this, the best way to start is to leave the computer to one side and use the telephone to dial the phone number to which you wish to connect.

It’s a simple enough first step and it’s one that will save you major headaches. You’ll be able to verify whether:

  • The phone number is in service;

  • The number dialed is indeed answered by a computer;

  • The phone is constantly busy;

  • You’re dialing the right combination of country and city codes;

  • You’re not dialing the area code when you don’t need to.

Most computers let you monitor these things via an internal speaker, but with dial tones and busy (engaged) signals that vary from country to country, it’s well worth the price of a 10-second phone call to dial the number once by yourself. Then, after you have verified that the number is functioning and available, make sure that it is the actual number that your modem will attempt to dial. Windows 95 does a good job adding or deleting country and city codes, but still it’s best to check each time.

When it comes to dialing, you can use the computer to dial or you can dial your number from the phone itself. In both cases you should first set your modem so that it does not wait to hear a dial tone before you dial (see this related article).

To use your computer to dial, place the receiver (handset) on the coupler, get a fresh dial tone, and then turn your computer loose to dial just as it would if it were wired directly to a phone line. In Luzern, we needed to dial ‘0’ for an outside line, so we manually inserted the zero, followed by a comma to produce a pause, right before the phone number the computer dialed.

It can be a little trickier to dial using the telephone’s keypad, but it’s certainly not impossible. (For full details on manual dialing, see related article)

Practice makes perfect

In the end, it’s clear that the use of acoustic couplers is something that must be practiced. Do yourself a favor and practice at home or in the office before you take your next trip. When you first start out you’ll be cursing and complaining, but with a little practice you’ll forget your early frustrations.

One last bit of advice: Be sure to pack along a RJ11 female-to-female adapter plug if you’ll be using your couplers with a PCMCIA modem. You’ll need one to connect the wire running from your couplers to the wire running to your modem.

The equipment

The PORT SureLink AcoutiCoupler 100 runs on a standard 9 volt battery which is included. It weighs 9.2 ounces with the battery installed and costs $135. One can order online from PORT’s Web site at, or by contacting PORT at 800/242-3133 or 203/852-1102. Other places to purchase acoustic couplers include Laptop Travel (, TeleAdapt ( and Mobile Planet (

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