using a cellular modem with a Dell Latitude notebook

Hands-On Review: using a cellular modem with a Dell Latitude notebook/laptop portable computer

July 21/04 - PLEASE NOTE: This article has been left here for legacy purposes (I scrapped my analog phone). You can read the updated articles about mobile internet at our new site:
June 7/99 - Being a systems administrator Adrian Biffen - Aerohost Web Systemsfor an international web hosting service is not an easy job. It requires constant attention to email, fax, telephone and server communications, with days that often run from 5:00 AM to midnight. Any notion I had about being able to travel for a few days without being in constant touch with our clients would quickly set the stage for the demise of our business.
   With this in mind, I decided it was time to implement a portable laptop or notebook system in conjunction with the cellular phone system that would give me the ability to leave the office from time to time and provide additional redundancy for the upcoming Y2K millennium adventure. This is the story of my experience ...

Some of the topics covered in this article:
  -using laptops and notebooks to connect to the internet via cellphone
  -connecting to the net using your long distance credit card via standard phone
  -using high gain antennas to boost cell performance
  -using dual hard drives for near instant data backup and recovery

   After spending many months researching the market, I decided to go with Dell Computer Corporation because it seemed like they had a good combination of reliability, top notch technology and support. The price was also reasonable, although somewhat higher than a 'no name' brand, but the cost is a secondary factor when you're dealing with a 'mission critical' situation as is the case with our business.

Some of the 'must have' features on our want list:

14" XGA (1024 x 768 pixels) screen with true color 24 bit display (16.7 million colors).
Touchpad and usable keyboard with inverted-T cursor keys.
Second hard drive capability for fast backup.
Reasonably fast processor (at least 300 MHz) with 64 Mb RAM
Built-in CD ROM, floppy and LS-120 superdrive.
S video out for DVD display on external TV.
Good battery life (> 3 hours) with fast recharge (1 hour).
On-site service warranty (international).
Durability and reasonable compactness.
Business lease financing.

   So I hit the Dell website flying with 'latitude' on my mind, configured the notebook the way I wanted and placed the order. The request was answered promptly and shortly thereafter, my machine was being prepared.
   I had already bought a 3Com (Megahertz) PCMCIA cellular capable modem, so I'll be ready to test the cell roaming capabilities when the notebook arrives by June 22. We'll be using an extra powerful cellphone and experimenting with directional antennas for extended area coverage (documented with pictures taken on our Nikon Coolpix 100 digital camera). I'll also be looking into the new Iridium and Globalstar satellite phone system as an alternative to the cellular system.

June 22/99 - I was just hoisting my third cup of coffee this morning when I heard a vehicle pulling up outside. Indeed, it was the courier arriving with the laptop. I signed off for it and eagerly opened the carton to inspect the contents.
   Everything was well packed, with supporting documentation visible as soon as the box was opened. I removed the accessory tray, pulled the laptop out of the plastic bag and turned it on ... voila! It booted up from battery, presented a welcome screen from Dell and, after entering the CD key number and a few other things, went straight into Win 98.

   I grabbed my Nikon Coolpix digital camera out of its nifty belt pack (anywhere, anytime, no developing), snapped a few pictures and then plugged it into one of the PCMCIA card slots. Windows immediately recognized the camera as another hard drive and I copied the JPEG files onto the hard disk, transferred the pix to a floppy, updated this article and finished my coffee. No fuss, no muss, no hassle!
   If I was going to use the camera to produce printed output, I would opt for a higher resolution model -but, for getting pix up on the 'net quickly, it can't be beat.

Dell CPt laptop

   Is this going to work as a desktop replacement for me? (I use a 17" Viewsonic in my lab, probably the best picture quality ever) - I think so, after seeing how bright and sharp the photo-realistic screen is (picture doesn't do it justice).
The 6.4 Mb drive failed and was replaced under warranty. The first replacement attempts were with several identical refurbished IBM drives which were defective upon arrival. They then substituted a Fujitsu drive which is still working today. Nevertheless, I wasn't pleased about receiving refurbished drives for a brand new, high end laptop - so I looked around and bought a new IBM 20 GB Travelstar drive, and it has worked extremely well, very quiet and fast.
I'll comment fully on it after I pick up my cell phone equipment and install the modem.

June 27/99 - The first thing that greets you when you power up the CPt is a welcome screen from Dell. When Windows launches, there are icons conveniently provided on the desktop that permit direct access to the html based documentation, so it really isn't necessary to read the hard copy manuals even though several are provided. Another nice touch is a Dell applet that prompts you to make floppies containing all the system drivers in case you ever have a catastrophic hard drive failure. These driver disks, along with the Win 98 CD will enable you to reconstruct your system quickly.
   After backing up my drivers, I decided to take a look at how the 6.4 Gb hard drive had been configured at the factory.
The back lighting for the screen started to fail, making it hard to see. The entire display unit was promptly replaced under warranty.
It turned out that it was divided into three partitions, all running the 16 bit FAT file system. I wanted the hard drive divided into two equal partitions (primary and backup) and I also had expectations of taking full advantage of the newer 32 bit FAT system so that I could maximize my hard disk sector and space utilization.
   However, if I changed the disk structure using the Windows FDISK utility, I would have lost all the data, including the pre-configuration of Windows that Dell had installed. This didn't seem like a good idea, so I elected to run out and purchase the Partition Magic program from Power Quest. This product allows you to re-configure your hard drive 'on the fly' without losing any data; in very short order I had the system running smoothly, just the way I wanted it, without having to re-install Windows, etc. It's the kind of program you hardly ever need, but when you need it, you need it bad!
   My next step was to transfer all the data from my desktop system so while I was out and about, I also purchased a special parallel port cable so that I could run the Windows Direct Cable Connection program. This is not the fastest way to transfer data, but it works well enough for a one-time or occasional activity. If I was doing this often, I would certainly purchase something like Laplink, USB hardware or a network card. After letting it run all night (yes, moving 2 Gb of data is slow), I came back in the morning and my mobile desktop replacement system was ready to go.
   The Dell laptops come with a built-in touchpad that works very well as a mouse replacement, largely due to the presence of a really nifty driver from Synaptics. It permits vertical page scrolling by stroking the right hand edge of the touchpad (likewise horizontal scrolling by sliding your finger along the bottom edge). It even let's you 'coast' through a long page if you swipe it quickly and let your finger fly off the edge, stopping the scrolling action only when you tap the touchpad (yes, you can control the speed). The more I use it, the better I like it and it certainly is handy when you just need to turn on the computer and do something easy, like downloading your email, without having to drag out the mouse.
   However, I still like to 'mouse around' so while I was out, I had also grabbed a new Microsoft IntelliMouse with the scroll wheel. When I plugged it into the PS2 port, the Synaptics driver recognized its presence and disabled the touchpad, allowing all the IntelliMouse features to come into play. I also installed the IntelliMouse driver, but discovered it clobbers the Synaptics driver for the touchpad (and doesn't really provide any additional functionality), so I used the driver disks I had made earlier to restore the Synaptics driver. The scroll wheel also works very well; when you click the scroll wheel button, you can scroll a page vertically just by moving the mouse up or down on the page - you don't need to move the cursor over to the elevator bar and click on it anymore. You can also rotate the scroll wheel to generate the same effect, but I found that this operation was not as consistent in all programs as the scroll wheel button is, although this might be something to do with the Synaptics driver.
The keyboard failed and was replaced promptly under warranty.
   By the time I reached this point, I was getting quite used to the new system and found that I was really starting to enjoy using it. Everything works well - the hard drive is fast and the CPU snaps programs up on the sharp, bright screen in a flash. I have also enjoyed the versatility of being able to swap various different drives in and out of the media bay. The battery lasts for over 3 hours and I find it very liberating to be able to move around and work wherever I want instead of being confined to my office all day.
The battery failed and I had to pay for a new one as the warranty doesn't cover it after a year. It was hardly ever used off 110 VAC, very few charge/discharge cycles, but it died (zero output all of a sudden) anyway. Of course, it was one of the few times I was using it on battery power and I lost data because of it.
   I haven't tried the specified torture test of pouring coffee between the 'h' and 'j' keys yet (from 4", with cream and sugar), but something tells me it really could handle this.
   Next, I installed my Megahertz/3Com cellular modem, hooked it up to my landline using the handy Xjack retractable connector and logged onto the net. The first thing I did was go to the 3Com website and download the flash upgrade for the modem bios. I ran the flash upgrade program, but when it reached the 10% stage, it quit the bios replacement and gave me an error message, something like 'file transfer failed'. A chill ran down my spine and then I broke out into a cold sweat as I realized I may have toasted the most expensive modem I've ever owned. I've heard some woeful stories about modems being destroyed during the flash process and I didn't need to find out that this had happened to me. I rebooted the laptop, hit the dial-up connect icon and muttered a short Bhuddist prayer. Much to my extreme relief, it logged on and even downloaded a new order from a client!
   I zoomed back to the 3Com website, but couldn't find any reference to the problem in their knowledge base. So, I picked up the phone, called their tech support and got a support person on the line in short order (toll-free). He knew exactly what the problem was and instructed me to reduce the buffer settings while the update was being performed. This worked just like a charm and my panic level subsided; faith in 3Com was restored.
   I had also noticed that I couldn't hear my modem dial-up when I was connecting to the net even though the speaker setting was on; although the PCMCIA modems don't have an internal speaker, they are supposed to be able to feed the line audio into the Windows sound system. This was troubling because I have learnt over time to interpret the handshaking signals (i.e. squawks and bleeps) and know when I've hit a bad modem or other problem.
   Since I had a few other minor issues to resolve, I decided to give the Dell mobile support team a quick call and see if they could help. The contact information is prominently displayed in the support notes and I found myself talking to a friendly technician in very short order. He was very helpful and we actually had a long discussion ranging over numerous topics; I found that he was in no hurry to dump the call. After hanging up, I tried the things he suggested, but unfortunately, it still doesn't work. So I've sent off some email in the hopes that they can find something else to try, but if they can't I still feel that they did a good job, especially since the modem is from another supplier. My guess, though, is that it's a problem with the laptop audio driver because the Win 98 'toggle keys' sound doesn't come through either (author's note: in the end, it turned out to be a bios problem, solved by the release of Bios version A01).
   Nevertheless, the modem is working fine and consistently logs on at 44 to 50k. The compression algorithms seem very good as everything downloads very quickly and I haven't yet had a failed connection, so not having the dial-up audio monitoring hasn't been much of a problem so far. I have also traveled out of our local calling area and tried connecting long distance to our modem pool, using my telephone credit card - it worked perfectly. If you try this, make sure you check the 'Operator assisted or manual dial' setting on the 'Options' tab for your modem settings. This causes Windows to bring up a dialog box when you hit the 'Connect' button; this allows you to manually dial your long distance number, wait for the tone and enter your credit card number. When the modem pool answers, you just hit the 'Continue' button on the screen, hang up the phone and the system logs on just as if you were at home ... works like a charm!

July 10/99 - The most difficult part of connecting to the 'net via cellular has been obtaining the correct data cable that links my laptop to the cellphone. There are numerous types available, depending on your cellphone model and your laptop modem. In the end, I had to special order the 'Mot1' cable for my equipment, which set our schedule back considerably.
   I have an older Motorola analog cellphone and I decided to stay with this for a number of reasons. The analog system has much wider coverage than the newer digital cells; it is also higher power and uses a lower frequency range, making it less line-of-sight. I'm not particularly concerned about the higher voice quality and enhanced privacy of the digital system, but the coverage issue is of paramount interest to me. The analog system gives me excellent coverage in all the areas I need and I am basically never out of touch because of this.

   Analog modems don't work with digital phones, so I couldn't see much point to having a 'dual system' cellphone. You can connect your analog modem to a 'dual' phone (provided it has the proper connector), but as soon as it detects a data operation, it will automatically switch to analog operation even if digital cells are available. Some digital cellphone providers allow you to connect through the digital system by attaching a cable from the serial port on your laptop to the digital cellphone (no analog modem is involved or required), but this will only work when you are within range of a digital cell. Since analog service is generally available wherever digital is (the converse is not true - yet), I couldn't see the point of mucking about with two different systems, hence I settled for a pure analog setup (for now). This also means that the cellphone costs are lower, although airtime is charged by the minute rather than the second.
   So, I connected my expensive data cable to my 3Com/Megahertz modem, held my breath, muttered another prayer and hit the 'connect' button to dial-up my service provider (Sprint). I watched in sheer disbelief with my 'net monitoring software (NetMedic) as the modem auto-deteced the cellphone connection and the phone number scrolled by on the cellphone readout. The system logged on at the (lately) unheard of speed of 4800 bps - wow, I thought, I'm ON!!

Cellphone Field Test
Field Testing

   I stared at it for a while, enjoying the sense of elation. I then began to wonder if I was experiencing an unfounded sense of joy since 4.8K is not exactly cable-modem speed. So, I opened my mail program (Netscape) and, voila, 14 new messages began pouring in. It wasn't as fast as I'm used to, but hey, it worked just fine - amazing! Then, I tried surfing some pages with large graphics and even that worked well enough to convince me that I didn't need to put my browser into 'text only' mode. I rattled off some quick responses to the email, logged off, and with a big smile on my face, cracked open a bottle of select brew that I had been saving for this occasion. I knew in that moment that a whole new era in my life had begun.

   I'll be field testing the system over the next week or so, seeking ways to optimize performance and reporting on the 'real world' trials.

July 23/99 - The screen froze just as I was sitting down to write a more detailed account of some of my experiences with cellular phone behavior when connecting to the net. Hmm, I thought, I'm sure I didn't hit the 'freeze' button and I've yet to have this thing crash on me, what's up? The short answer is that my IBM hard drive went south and I've just spent two days going through computer hell ...
   I had purchased the next-day onsite service policy when I bought the laptop, so I quickly got on the phone to Dell tech support to see how they could help. My call was answered promptly and after running a few diagnostic tests with the tech over the phone, he decided we wouldn't waste time with a service call - they'd just send another hard drive right away by overnight courier. Sure enough, it arrived as promised at 11:30 the next morning.
   The primary hard drive is removed by releasing a single screw on the side of the laptop, so sliding the bad one out and replacing it with the new unit was simple. However, I now faced the daunting task of rebuilding my system. Yes, I had backed up my critical data onto my 120 Mb 'super floppy' disks, but I still needed to re-install Windows, all the system drivers, all my programs (and finding all the danged program serial numbers) and some more data that I had archived on our office network system.
   I had decided not to buy the second hard drive when I purchased the system as it is a relatively expensive option. I'm becoming long in the tooth when it comes to rebuilding computers and I decided this was to be the last time I go through this. The fact of the matter is that hard drives fail, no matter how old they are, who makes them, etc. The only workable solution I've found is to run dual hard drives as we do on our office network system, one being a bootable copy of the other. So, I picked up the phone and ordered the second hard drive; when it arrives I'll discuss the setup I use for this configuration.
   Meanwhile, I've got my system back up and running so I'll be writing more about the cellular experience shortly ...

July 28/99 - I owned a communications design/build business for over a decade, so experimenting with UHF (Ultra High Frequency band) cell reception is almost second nature to me. I say 'almost' because there are certain peculiar anomalies associated with the cell system and it has taken some time to understand some of the characteristic behavior I have observed, especially when connected to the Internet. I decided to keep things simple for the first part of this evaluation, so the comments in this section apply to my experiences without any external antennas or high power 'bag' phones; I'm just using a Motorola hand-held 'flip phone' for now.
   The analog cell system was designed primarily for voice communications, not data, and it works better for the former. The switching circuitry at the cell site is capable of performing all kinds of bandwidth management tricks to better handle call volume, particularly during 'dead air' moments that occur regularly with normal conversation. An almost impertecptible pause in human speech patterns is actually a long, wasted period of time for electronics that analyze time domains at the microsecond (one millionth) level, so the system is designed to switch the circuit away from you during those very brief periods and hand over the 'airtime' to someone else that needs it at that moment. This can be problematic for data circuits that exchange handshaking pulses and expect measured responses in very short periods of time.
   Fortunately, our local provider allows us to prefix the call with a special code that alerts the cell to the fact that it is handling a data call, which causes it to react differently. I've found that this usually means the difference between connecting at 4800 bps (without the data prefix *3282) and 9600 bps (with the prefix) - a speed difference of 100%. Not all providers incorporate this feature - I certainly couldn't use it in Washington, Idaho or Montana, although I occassionally still connected at 9600 bps without it while in 'Roam' mode in those states.
    If the cell is busy, especially combined with a weak reception condition, you can expect your 'net connection to get dropped when you're right in the middle of downloading your mail, just as it used to with the feeble modem connections we experienced on the regular P.O.T.S. (Plain Old Telephone System) land line. This will usually happen when someone sends you some unsolicited spam mail with a large file attachment full of colorful graphics. Naturally, because the incoming mail delivery wasn't completed, your remote mail server behaves properly by re-sending the mail from the start of the first message in the waiting batch as soon as you re-establish your connection and you're on only long enough to find that the same thing happens again. When this occurs, say three or four times, you may find that the air around your current location becomes quite colorful too (usually blue).
   However, there are some things you can do to alleviate this condition. A short, 5 minute drive to another location (especially higher ground) can often bring the cell signal level up to a much higher level, with a corresponding boost in the integrity of your connection. If you're near a highway, try and move off of it down a side road - aluminum-sided trucks make great rolling reflectors at these frequencies. Also, keep in mind that fog, heavy rain and electrical storms can all have a negative impact on your level of success. Don't even think about connecting to the 'net if you're in a moving vehicle or a boat unless you can hit the cell tower with a water pistol.
   If you are travelling through a popular tourist destination area, it can also be a good idea to keep going until you reach the next cell that may not be so busy. A fully loaded cell may try and hand you off to another cell some distance away that actually is out of reach, causing your signal strength to jump back and forth between 'good' and 'no service', a very confusing experience. If you're staying in a resort area that has only one local cell that is running at capacity, you may get better results by waiting for off-peak times.
   If you can't move, most email client programs have menu driven options that allow you to block messages larger than a certain size from being downloaded, so you can temporarily prevent the large spam message from being downloaded while you collect the rest of your critical mail from the server. If you do this, keep in mind that you'll eventually have to remove the block and download the message to properly reset your mail queue. I've also found that it is much better to log on frequently and collect mail in smaller batches during the day, rather than waiting for one big one at the end of the day.
   In summary, I've found the analog cell coverage to be quite good and I've managed to maintain regular communications, albeit with the help of some of the above techniques from time to time. It seems to be available in all the places I've wanted to go, so I'm not about to order my Iridium or Globalstar account yet. I lost it at the 6600' level going through Logan pass in Montana, but it came back quickly as we descended to St. Mary's Lake. Yes, it can be painfully slow at times, but overall I have to say it has worked well and has never interfered with my daily work. (yes, I'm well aware I haven't received my first cell bill yet). You'll learn quickly how to monitor your signal strength meter as you travel and pick the good spots to log on ...
   Of course, you may often be staying in a hotel or motel where you have a phone available. If this is the case, it may be more practical to use your telephone credit card to connect to your dial-up service provider (say goodbye to roaming charges and 4.8k). Windows has a setting in the modem options under Dial Up Networking that allows you to make a 'manual dial' call. If you check this option, it will wait until you dial the number manually and enter your credit card number. I carry a dual outlet plug that allows me to connect both the phone and the modem into the line at the same time for this purpose. You'll need a phone system that has a jack either at the wall or base of the phone in order to do this.

Visit one of our clients for some more cell information: Gecko Beach

Office with a View

Good Cell Location

August 9/99 - My second hard drive arrived today for my Latitude and I put it to work immediately, since I have firmly resolved not to spend another microsecond in computer hell. It slides easily into the exposed media bay slot and locks in place, so the physical installation is about as simple as it gets. The software aspect is a little more complicated, but not too difficult if you know how.

The expensive second hard drive failed 3 years later, just after the warranty expired. It was only used occasionally as a backup and was never dropped. I replaced both internal drives with the new IBM Travelstar 40GNX 20 GB drives - super quiet, super fast and affordable ... these days, you can simply buy a USB hard drive that plugs into your USB 2.0 or firewire port - makes a great backup solution! 

   First, you want this to be a boot drive so that it can take over at a moment's notice if your primary drive fails. The easiest and safest way to prepare it is to remove the existing primary hard drive and boot the laptop from a floppy (you'll need a boot floppy with FDISK.exe and on it). The new drive won't be recognized at first (after you've booted from the floppy) because the boot sector needs to be set with FDISK, but once you've done that, it will come up as the primary hard drive 'C'. Then, if you run with the '/s' switch, it will be bootable as your primary drive.
   Next, you'll want to re-insert your original hard drive so that the new backup drive becomes the secondary hard drive. After that, you'll be ready to copy the contents from your primary hard drive to the new backup hard drive. So, you go into Explorer, click on the root folder of drive 'C' and attempt to copy it to drive 'D'. You then get an error message that says it can't be done and you're sitting there, scratching your head, wondering why Microsoft won't allow you to duplicate your hard drive ...
   Fortunately, there is a way to do it (without buying a program like DriveCopy). First, you should temporarily disable the Windows swap file (Control Panel > System > Virtual Memory). Then (after a reboot), use this variation of the dos XCOPY command:

xcopy C:\*.* /e /h /k /r /c D:

   This will copy every file from your primary hard drive over to your secondary drive. Note that this must be run from a dos window while Windows is active. This command should only be used the first time you copy to a freshly formatted drive. From this point on, you should use this variation of xcopy, which will monitor the file archive bit and only copy those files that have changed:

xcopy C:\*.* /e /c /i /h /r /m D:

   You can put this command into a batch file and run it from a desktop icon. The result: a fully bootable backup drive that does the job in less than 20 seconds a day for most users! If your primary drive fails, you just hit the setup button, change the 'first boot device' setting to the media bay hard drive and voila! - you're back in business while you wait for your primary replacement drive to arrive.

September 4/99 - Low signal levels do have an impact on the efficiency of data transmissions while connected to the net via analog cellphone. If the signal strength is poor, the connection will hang for a number of seconds, continue transmitting data, then hang for a few more seconds. This stop/start/stop/start behavior can become tedious, not to mention the effect it has on airtime charges. It is especially annoying when the connection is dropped altogether and the call has to be re-established and the mail download started all over again.
   I have experienced these fringe situations enough at this point to want to do something about it. I purchased a new Motorola DP 650EV (the 'V' means you can set it to vibrate so that your pocket doesn't ring) so that I could be confident of having the latest circuitry - it seems to work better than my older 650, but I don't like losing the 6 stage S meter (new one has only 3 levels of signal strength). The Motorola phone also allows you to remove the built-in rod antenna and plug in an external antenna, as you can see in the picture below. I used industrial grade Velcro to attach the cellphone to the edge of the laptop screen.

   Next, I bought a marine whip antenna (no vehicle ground plane required). This was a waste of money as it didn't perform any better than the built-in rod antenna on the cellphone. I then exchanged this for a Larsen YA5 800 directional yagi antenna (9 Dbi forward gain) that you can also see in the picture below. This made a big difference; since I have been using this in fringe areas, I've had no trouble at all with my net connections.

Yagi Antenna Setup
Yagi Directional Beam Antenna

   I'm going to use a shorter cable since line losses at these frequencies can be quite significant, but even with this long length of cable it is a marked improvement. Note the correct rotational positioning re vertical polarization. A slight tilt on the horizontal axis can also improve signal if the cell site is high up on a mountain. The narrowest elements are at the front of the antenna (pointing end).

   I'll be field testing the system some more over the next few months, seeking ways to optimize performance and reporting on any significant improvements. In January or February of 2000, the Iridium global satellite system will become 'internet enabled' and we hope to be able to test the net capabilities at that time.
I ended up using the Globalstar satellite phone; see the Globalstar satellite phone review ... I also replaced my analog phone with a Nokia GSM phone.

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