FAQS! FACTS! FAX! 081 (28/10/97)

LIGHTNING STRIKES AGAIN

Here in Indonesia we are approaching the rainy season and the storms expected over the next few months will certainly be dramatic as usual. The lightning is impressive but there’s usually little or no warning, hence my concern. My PC is connected to a US Robotics 56kbps modem, to simply unplug it -- as advised by F!F!F! 23/09/97 -- is obviously the simplest solution but so easy to forget. This would also leave me disconnected for much of the time. There must be other alternatives?

Randall Riding

A

The only sure way to protect your equipment from a direct lightning strike, to power or telephone cables immediately outside your home or office, is disconnection. The electrical potential of a strike can rise to several tens of millions of volts, more than enough to arc over and fry any electronic component that gets in its way. However, there are several devices that can filter out high voltage spikes and surges, caused by the effects of an indirect or nearby strike. One of the leading companies in this area is Atlantic Scientific Corporation. ASC manufacture a wide range of surge protection devices, including stand-alone phone and mains filters. They also make a combined ‘multimedia’ model, with mains and phone surge protection built into a single multi-way socket. This is marketed in the UK by Bowthorpe EMP, telephone (01273) 692591, it sells for around £50. This model is fitted with UK 3-pin mains and BT phone sockets, which are obviously different to the ones that you are using. Details of surge protection devices designed for the Indonesian market, and local suppliers, can be obtained from ASC direct, via their well-maintained web site on: http://www.iu.net/atlsci/index.html

VOLATILE VOLTAGE

The electricity supply in this part of England is so capricious that I do not dare leave my PC switched on when it is ‘idle’. The slightest wind, rain or thunder storm seems to produce unpredictable blackouts. Surely we have the technology to combat lightning and power failures?

Patrick Macdonald, Great Eversden, Cambridge

A

National Power and your local electricity supply company cannot yet control the weather, or the fates, but you can get a device called an uninterruptible power supply or UPS, that will protect your PC from the vagaries of the electricity supply. A UPS contains a rechargeable battery and a device called an inverter, that converts the DC voltage from the battery into 240 volt/50Hz AC mains. The UPS connects between the mains socket and the PC, it has a regulated power supply that irons out spikes, surges and minor fluctuations in the mains supply. If the mains voltage falls below a specified level, or cuts out altogether, the inverter takes over, to maintain the supply. How long the UPS can operate depends on the capacity of the battery. It can vary from a few minutes, to several hours. When the UPS detects a problem there’s normally some kind of audible warning or alarm, so you can safely backup your work, a few top-end models will even do that for you. American Power Conversion (APC), one of the worlds largest manufacturers of UPS, have a very informative web-site at: http://www.apcc.com/

CONTROLLING INTEREST

I am interested in hooking up non-IT kit up to a PC, to open and close doors, curtains, alarms, garage doors, videos, cameras etc. Do you know of any companies or web sites that I can contact ?

Sean Peffer

If you’re handy with a soldering iron and know your way around a circuit diagram then it’s well worth visiting: 

http://www.hut.fi/Misc/Electronics/

Circuits/parallel_output.html

There you will find details of how to build a simple interface circuit, that connects to your PC’s parallel port, to operate a relay or switching device. There’s also software and programming information, plus links to other related sites. Information about a PC control system that can operate almost every appliance in your home can be found at: http://ourworld.compuserve.com/ homepages/mark_gilmore_2

Maplin Electronics have a range of plug-in I/O controller cards, switching devices and control software. They can be reached at (01702) 55400

INDIA ON-LINE

Regarding the query in F!F!F! (India On-Line 21/10/97) about the reader who wanted to access their e-mail whilst staying in Southern India. There is a global Internet roaming service called iPass that allows local call access with an existing Internet account, more or less anywhere in the world.

Bill Unsworth

A

iPass is a global alliance of Internet service providers (ISPs), providing e-mail services for subscribers, between member companies. The list of countries with local dial-up points of presence (POPs) is most impressive, and growing all, the time, unfortunately it does not yet include any Indian ISPs, though they tell us they are working ‘aggressively’ to open up that market. Nevertheless, anyone planning an overseas trip, and interested in retrieving their e-mail from out of the way locations should check if their ISP is an iPass partner, or check the iPass web-site at: www.ipass.com