Get IT Done: Mobile-computing connection methods and connection types

Become familiar with the basics of connection methods for mobile data support

Mobile computing has been undergoing a bit of a renaissance lately. A few years ago it was a simple matter of finding a data-compatible mobile phone, a PC card modem, and a matching cable and installing it as a modem. Then people started to use PDAs as well. Cell phones started to come with infrared ports to allow communication with laptops. Then cell phones started to come with modems built in.

The thing that held mobile data back for a long time was the slow data rate achievable using the cellular networks, which until recently, offered a maximum data connection rate of 9600 bits per second. This was fairly simple to configure.

Now things have become more complicated. There are phones built into PDAs; PDAs built into phones; cameras built into phones; phones that connect using serial cables, USB cables, Bluetooth, and infrared; and phones that won't connect at all, no matter what you try.

If there is technofear among users of normal IT solutions, it is multiplied when you start to add the wireless element. There really isn't any need for this. If you imagine that the phone is simply providing the modem connection, you can usually treat the connection in the same way as you would a dial-up POTS service.

Here are a few basics about today's mobile computing that may aid help desk pros to communicate with their users and help them troubleshoot their problems.

Connection methods
  • Serial cable: Serial cable was the standard way to connect data-capable phones, but it is becoming obsolete, as many new laptops do not have serial ports anymore.
  • Infrared: Infrared is the first of the wireless methods of connection. Anyone who has used infrared with Windows-based systems will know that the standard seems to vary from one version of the OS to another. With the latest version of Windows XP, the infrared support is quite remarkable. All you have to do to install the infrared modem is to activate the infrared port of the phone and point to it. The drawback of infrared is that it requires a line-of-sight connection and is prone to interference from other IR sources and sunlight, making it harder to use in the open air.
  • Bluetooth: Bluetooth is basically a short-range radio system that can link devices together in the same way that cable does. With a range of 10 to 100 meters, it is used for wire-free headsets, mobile phones, and connections between portable computers and phones. The link can be used for dial up connections and for synchronizing the address book of the phone or a PDA to a PC.

Connection types
  • Dial up: In the beginning, there was a rather slow 9600 BPS dial up available to mobile users. It was all you could get and many people weren't interested in it. It was OK for retrieving text-based e-mail but that was as far as it went. This was the stumbling block that prevented many people from entering the market.
  • HSCSD: This was enhanced with the introduction of High Speed Circuit Switched Data (HSCSD), which allowed the bundling of two or more carriers, each working at 14,400 BPS, working in a similar way to ISDN, although not as fast. Not many mobile service operators adopted this system, as the next generation of connection was already on its way. It was costly because the network would charge for both carriers.
  • GPRS: Soon after the introduction of HSCSD came GPRS. GPRS has very high theoretical speeds of connection and, if the standard 9600 dial up was equivalent to the dial-up connection and HSCSD was equivalent to ISDN, then GPRS would be the mobile equivalent of ADSL. This connection is no longer a dial-up or circuit-switched system but now is an "Always on" connection. It delivers connection speeds roughly the same as a home 56K dial up, which is far more attractive to end users.

Factors that can affect a connection
Users of mobile or cellular phones will understand all too well the problems that can affect the reliability of a data-over-cellular connection. The weather, distance from a cell phone tower, metal-framed buildings, mountains, and much more can reduce the strength of a signal and the quality of the connection. With a data connection, these effects are amplified because, unlike the voice call, the data signal does not receive the same sampling and filtering and will be more reliant on a good signal between the handset and the cellular base station.

One of the first things to check when troubleshooting a mobile connection is the signal strength. If it is less than 50 percent, it may not be possible to make a reliable connection.

Provision of data services
Data calls do not use the same carrier as voice calls. It is possible to dial a modem from the mobile handset and hear the modem squawks but be unable to make the same connection from the dial-up software. Some network providers allow data calls by default, and you will be able to make a connection without any problems. Others require a special provision to be switched on in your cell phone account.

If you wish to use faster connections methods, such as GPRS, the method of connection is somewhat different. Instead of dialing a number, you send a request to the handset to switch on the connection and specify a connection server. The mobile network then effectively becomes your ISP, which can lead to other difficulties, such as needing to find an open relay SMTP server for sending e-mail. The mobile network often provides these open relay SMTP servers and you would need to check with them for the name.

Mobile data support
Mobile data is going to be a more important and significant part of life for support services in the future. It continues to change and develop at a frightening rate and what applies today may be old news tomorrow. It is an interesting area for support and one in which help desk pros will become more and more involved in the future.