BMUG Revelations/BMUG Revelations.toast/Utilities/Random/Travelling & Phones/Phones In Germany

Text File | 1992-05-25 | 6KB | 135 lines

Installing a modem in Germany can be a very time-consuming job. The PTT comes
with two wires (named a and b, b=Ground), but then there are several
different possibilities. This notice here gives some hints.

First you must know, that the german PTT has a different concept. If you have
more than one device on one telephone line, and one is active, all other must
be dead. The PTT tries to garantie privacy. This concept leads to the fact,
that if you have devices in parallel (this is forbidden), and one device is
dialing, the other will ring or detect a ring. The privacy concept depends
therefore on special switching facilities build into the telephones.

Old style connector:

                  VDO4 Connector:

                  4  3  2  1          a and b  the telephone wires
                  |  |  |  |          E        means the local Ground (Earth)
                  E  W  b  a          W        is the Bell (German: Wecker)

The normal telephone connects a and W, if the handset on the telephone. (It
drives a second bell, perhaps). If you pick up the handset the connection of
a-W is opened.

                  VDO7 Connector:

               7  6  5  4  3  2  1
               |  |  |  |  |  |  |
               G  E  W  b  a  b' a'

This connector is used at the main-device, if two devices are connected
to the line.  a' and b' are driven from the connected device and go to
the second telephone. But the same connector VDO7 is used, when a modem or
automatic answering system is installed. In this case the ADO8 connector is
the first connector.


                  ADO8 for Modems:


               a --- 1       8 --- a'
               E --- 2       7 --- W
               G --- 3       6 --- Z
               b --- 4       5 --- b'


If the ADO8 Plug is not inserted, two internal switchec connect a with a' and
b with b'. So if you want to connect somthing to the telephone line, you can
simply use the pins 1 and 4 of the ADO8. But if you want to use the telephone
behind properly, certain connection have to be made, depending on the type of
equipment, that is installed.


Sometimes you find ADO4 Connectors:


               a --- 1       8
                     2       7 --- W
                     3       6
               b --- 4       5 --- E

The ADO4 has also two internal switches for a and b. But the other sides of
the switches are connected to internal screws.


New connectors TAE6:

The connector type TAE is available from TAE6 to TAE16, depending on the
pin count. Mostly TAE6 is used. In the future it is planned to use the modular
jack adapter called "western"-connectors from german PTT. But at this time
TAE6 is installed for new lines.


                  1   2   3          4   5   6
                  |   |   |          |   |   |
                  |   |   +- G    E -+   |   |
                  |   +----- b    b'-----+   |
                  +--------- a    a'---------+

The logic is just the same as with the above ones. The TAE6 connects a with a'
and b with b', if the plug is not inserted. But like the ADO8 the TAE6 can be
coded as N (normal) and F (TeleFon). A modem is connected to the N-coded TAE6.
But the coding can be overwritten, if you use a bit more energy when inserting
the plug (The other possibility is to cut the coding with a knife from the
plug).

Now, if you have a jack adapter, what can be done?

First, there are smome converters available. They are available from ADO8 to
TAE6 (working with all equipment modems/answering machines). And there are
converting adapters from TAE6 to Jack (RJ11). Normally they do garantee to
give you access to a and b, but they do not garantee that the other equipment
is working well.

(With the Worlport Modem series, we sell Cables one side Jack, other side
TAE6, coded as F or N, and direct connection between a and a'and b and b'.)

The best is, to bring along a modem plus thelephone. And if you find a and b,
all will work fine, but make shure, that you use the CCITT-Make/Brake ratio
for dialing. Otherwise you will often get a connection to a wrong number.

Additonally there is another barrier. Some, especially the older systems, need
a special switch to let you access the PTT lines, when you are connected to an
inhouse system. This is done by connecting E with a. If you need such a
switch, only approved modems will offer it. The corresponding Hayes command is
">" or ":", depending if the modem goes offhook before or after the modem goes
online.

I'm sorry, there is no simple rule how to get online with a modem. It
mostly make sense to travel with a screw-driver and clips. Or to use cups.
(We can supply you with the Tandy-Cups for the Worldport Modem series, as we
are Tandy dealers (send EMAIL). Please note, that the European Tandy-Cups are
different from those in the US. Most European ones, with a PTT sign are not
able to operate at 1200 Baud. Therfore we sell the US-Originals, which even
sometimes work with 2400 Baud).


I know that this text is not complete. There are special switching units
called AWADO1 and AWADO3. They allow to use two devices on the same line. But
instead of simply using the lines a and b, they need the W signal from the
telephone device to work properly. And the german PTT uses several different
diagramms. Often int is not easy to find out, what sort of diagramm was used
and why. But I hope that you are now able to find a and b on all sorts
of connectors! If you need a special advice, send EMAIL.


    RzK D.Kpke, Bitzenstrasse 11, D-5464 Asbach Ww., FAX [phone]

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