[comp.dcom.telecom] US Phones in the UK and Vice Versa

OLE@csli.stanford.edu (Ole J. Jacobsen) (06/12/90)

I have just returned from the UK with a few toys in my bag:

You can now buy UK-style modular plugs in electronics shops (including
Tandy [Radio Shack]) in the UK. These can be attached quite easily to
a US linecord if you follow the instructions below. This will allow
you to attach a US phone to the UK network. While this is not legal of
course, I have verified that it works. Using a BT extension socket, I
have also made a UK test jack with a US "tail" so that UK phones with
the modular jacks can be plugged into US systems. This too is probably
not legal, but if you own your own PBX.

Note that the UK modular plugs cannot be had from British Telecom
shops, since this would allow you to plug non-approved apparatus into
their system, but run down the road to a Tandy or somesuch, and you're
all set. Extension cords and do-it-yourself jacks *are* available from
BT. The way you are supposed to install extra jacks is rather amusing.
The "master socket" is considered holy, so you plug a converter
(splitter) into it (rather than punching down your own cable) and run
cable to the extension socket(s), unless you have a "new style
linebox" in which case you *can* attach the wires directly. BT sells 9
different "kits" (including one which contains "50 cable cleats," we
call those "clamps" over here I think...)

To attach a UK modular jack to a US cord:

1. Remove about 1/2 inch of the outer insulation to
   expose the 4 wires: black, red, green, yellow

2. Cut the black an yellow wires away.

3. Spread the red and green into a V-shape and insert
   carefully into the UK plug. Note that the wires should
   go to pins 2 and 5, which, on all the plugs I was able to find,
   corresponds to the outer-most connectors.
   This is a bit surprising if you are used to US modular plugs. *

4. Using a vice, good pliers or similar, squeeze the plug together,
   so that the connectors crimp onto the wires. Some suppliers will
   include disposable "thingy" to aid you in this process. This 
   "thingy" (die) also drives the strain-relief home. You could also
   buy an expesive tool for this purpose.

5. Assuming there is a US modular jack (and phone) at the other end
   of the cable, you are now ready to play.

* Note: This means that pins 1 and 6 are missing from the plug, and
according to a previous poster 1 and 6 are reserved for ISDN so that
makes sense. Also note that these plugs are impossible to find in the
US, but I wonder if you could order them through Radio Shack, since
the pack I got in Tandy has a proper Archer stock number.

** Note also: The above does not take into account any bell-tap
prevention for UK phones connected to US networks. See previous poster
on the use of capacitors etc. I have not found bell-tap to be much of
a problem since any other phone on the line would typically be
touch-tone and thus not generate much "spark".


Ole

mb@sparrms.ists.ca (Mike Bell) (06/14/90)

OLE@csli.stanford.edu (Ole J. Jacobsen) writes:

>You can now buy UK-style modular plugs in electronics shops (including
>Tandy [Radio Shack]) in the UK. These can be attached quite easily to
>a US linecord if you follow the instructions below. This will allow
>you to attach a US phone to the UK network. While this is not legal of
>course, I have verified that it works. Using a BT extension socket, I

"It works" is a matter of interpretation. The mark/space ratios for
pulse dial phones differ (most of the UK is pulse dial only) and US
pulse dial phones will therefore give wrong numbers on some exchanges.
ie. this is an "it may work but don't rely on it" method.


Mike Bell -- <mb@sparrms.ists.ca>

ashbya@uunet.uu.net (Adam J. Ashby) (06/15/90)

mb@sparrms.ists.ca (Mike Bell) writes:

>OLE@csli.stanford.edu (Ole J. Jacobsen) writes:

>>course, I have verified that it works. Using a BT extension socket, I

>pulse dial phones differ (most of the UK is pulse dial only) and US
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Most of the UK is both tone and pulse dialling (tone dialling is
free!)  and is increasingly digital due to aggressive System X and
System Y replacement.  In my opinion, BT offer a far superior
telephone service than I experience here in Illinois, even though they
don't (yet) offer all those wonderfully use(less)(ful) features that
we have here.


Adam