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Portable communication terminal
- wanted item
PX2000 was a small advanced hand-held terminal, intended for on-the-road
word processing and communication. It allowed encrypted messages to be sent
over standard telephone lines, using the built-in acoustic coupler.
The PX-2000 was introduced by Text Lite in Ireland as the successor
to the PX-1000. In The Netherlands, the PX-2000
was sold by Philips.
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The image on the right shows a typical PX-2000 unit with its cream coloured
case, ready for use (i.e. with the lid open). The lid contains an 8 x 80
character display, making it suitable for advanced word processing,
spreadsheet and terminal applications.
The PX-2000 contains a word processor, calculator, spreadsheet and full
data and text encryption/decryption facilities.
Furthermore it contains terminal emulations for DEC VT52, VT100, TTY and
VIDEOTEXT, allowing it to be used with a variety of services.
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A full-duplex modem is available through the acoustic coupler at the rear of
the PX-2000. The coupler can be detached from the device, so that it can be
used easily with any telephone handset (see below).
The modem sends data at 300, 600 or 1200 baud, whilst
receiving simultaneously at 75 baud. The latter is used for the VIDEOTEXT
terminal emulation mode. The data format is 8N1 (8 data bits,
no parity and 1 stop bit).
The PX-2000 is also backwards compatible with the older
PX-1000, in which case it uses simplex communication
at 300, 600 or 1200 baud 7E2 (7 databits, even parity and 2 stop bits).
This mode is called PX-1000 text mode [B].
When communicating with another device, the PX-2000 will detect the required
protocol from the header of the first data packet. If necessary, it will
automatically fall back to PX-1000 compatible mode.
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Two different versions of the PX-2000 were available. They each served a
different communication standard, so that a suitable version was available
for each country in the world, depending on the local telehone network.
The following versions are known:
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- PX-2000, version 1
This version is compatible with CCITT V23 and BELL 202 standards.
It supports both C-Mail and VIDEOTEXT emulation (1200/75 baud).
- PX-2000, version 2
This version is compatible with CCITT V21 and V22 standard, as well as
BELL 103 and 212 standards.
This version can not send and receive messages from the Text Lite C-Mail
system which requires the V23 standard (version 1). Furthermore, VIDOTEXT
terminal emulation is not available in this version (as it also required
the V23 standard).
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The PX-2000 contains a flexible modem with an external acoustic coupler.
The modem can be used in simplex, half-duplex or full duplex mode.
In full-duplex mode it can only be used as a VIDEOTEXT terminal,
which was common in those days.
It allowed outgoing data to be sent at 75 baud, whilst receiving at 1200 baud.
In The Netherlands, VIDEOTEXT was known as VIDITEL.
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The acoustic coupler can be detached from the rear
of the terminal, and stays connected via a short cable with a 3mm jack
connector.
It has a microphone and speaker, that are separated by
two telescopic arms
that can be extended to match the size of the telephone's handset.
Furthermore, the microphone and the speaker are spring-loaded
so that they will automatically be positioned at the correct angle.
Coupler and handset are usually kept together by means of the supplied
rubber clip. If it is missing, a rubber band can be used instead.
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The PX-2000 has a fully implemented asynchronous RS232-compatible serial port,
which is available at the right side in the form of a
mini-DIN connector (see the rightmost images above).
It allows speeds of 75, 150, 300, 600, 1200, 2400, 9600, 19200 and 38400 baud,
offering hardware handshaking (RTS/CTS) or software handshaking (XON/XOFF).
Baud rate, handshaking and data format are all user configurable.
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Each PX-2000 terminal has an exchangeable memory module which can be accessed
from the rear.
After unlocking it, it can be shifted sideways
and removed.
A row of gold-plated slide contacts, mate with a similar set of contacts
at the base of the terminal.
External memory card with a capacity of 8KB or 24KB were available.
The memory card contained static RAM, which was retained by a small
backup battery on the card.
It could be replaced whilst the card was inserted in the terminal.
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- 8 lines x 80 characters variable contrast LCD
- Exchangeable 8K or 24K memory module
- Simplex, half-duplex or full-duplex modem
- Fold-out acoustic coupler
- RS232 compatible serial communications port
- Real-time clock with alarm
- Fully secure data encrypt/decrypt system
- Spreadsheet and calculator facilities
- Rechargeable battery pack
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- DEC VT-52 terminal emulation
- VT-100 terminal emulation
- VIDEOTEXT terminal emulation
- TTY terminal emulation
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- Cees Jansen (former cryptographer at Philips Usfa/Crypto)
Interview at Crypto Museum, August 2011.
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© Copyright 2009-2013, Paul Reuvers & Marc Simons. Last changed: Friday, 11 May 2012 - 20:00 CET
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![PX-2000 courtesy Cees Jansen [1]](img/301284/010/full.jpg "PX-2000 courtesy Cees Jansen [1]")
