Foreign Phones & Modems

Using Foreign Phones in the UK & UK Phones Overseas

Over the years different countries developed different standards in telecommunications, often as a protective measure for their own telecomms industry.  In recent years the market has opened up and approvals are now valid throughout the EC for example.

However, although in most cases foreign equipment will function  in the UK its performance may be unsatisfactory.  US equipment in particular uses different microphone amplifier sensitivity and receive amplification so may give unsatisfactory performance in the UK and vice versa.

A common problem is encountered when taking a UK phones overseas - it won't ring.  This is because most overseas countries use a 2 wire system and the UK 3rd  wire for the ring signal is absent.   The simplest way of getting around this is to ensure you take a BT MASTER (not slave) socket with you when you go.  Connect the 2 wires on the foreign system to connections 2 and 5 of the BT Master socket and plug the phone in.  It should now ring.

Foreign Cordless Phones in the UK

Foreign cordless phones invariably use bits of the Radio Frequency spectrum not allocated for phone use in the UK.  In some cases this will lead to interference to the phone from other users or the phone interfering with the rightful users of the frequencies.  It is not practical to modify these phones to make them legal in the UK and they are best avoided.

Modems and their Problems

Modems and their Problems

This isn't a treatise on the multifarious reasons modems don't work - just a short explanation of how to ensure they at least have a chance by getting the wiring right.  Firstly consider all the usual wiring problems, some modems use only two wires, others need three and won't auto answer without the third.  Wire all three correctly and you can't go wrong.  Many modem problems are simply caused by incorrect wiring of extension sockets. 

Nearly all modems these days have a removable lead with a BT plug on one end and an RJ11 on the other.  The most common configuration is from  the center two pins on the RJ11 to the outer two on the BT plug, HOWEVER, this isn't universally true by any means (despite PC World selling "universal" modem cables!).  US Robotics for one used a different configuration as do a number of Rockwell chipset internal modems.  If the lead you are using isn't the one that came with the modem you can't altogether trust it (unless its worked OK  in the past).  The fact it works on another (different manufacturers) modem means nothing.  As many people collect odd modem leads over time its worth (once you have the thing up and running) checking all your leftover leads to see if they function with your current modem, it can save much grief later (he says from experience).

Running a modem on a long extension lead isn't going to degrade the signal significantly however trailing leads easily get damaged so ideally wire up a proper extension as explained above.

Some modems are polarity sensitive, especially imported ones. 

Dial Tone detection circuitry on some modems is also quite fussy.  If you have the BT answering service (Call Minder?) which gives an interupted or modified dial tone when you pick up the receiver then often modems connected to that line will give "no dial tone".  The cure is to remove call minder or set the modem initialisation string to ignore dial tone detection.

If your calls drop make sure you don't have call waiting enabled, the call waiting tone often causes the modem to drop the line.  Similarly if you have other extensions on the line then even the briefest lifting of another phone will cause the connection to drop.  In this case replace sockets with privacy sockets or use privacy adapters, these stop other extensions affecting the one engaged in a call.

Any other tips for this section will be gratefully received.