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Telecom Instruction
B MARKETING
4 Commercial
J0023
Issue 2, August 1981
TELEPRINTER No. 23B/50 (TELEX) AND
No. 23B/75 (PRIVATE TELEGRAPHS)
1 INTRODUCTION
This instruction describes Teleprinter No. 23B/50 on telex and its variant
the Teleprinter No. 23B/75 on private telegraph circuits, the modes of operation and
facilities that are available on both machines.
2 GENERAL DESCRIPTION
The Teleprinter No. 23 is a semi-electronic teleprinter compatible with the
existing teleprinters on the telex network and on
private telegraph circuits. The extensive use of electronics, reduced
mechanical content, and modular
construction make it relatively easy to maintain. The keyboard and control
keys are designed to make operation simple and
introduce improved and easily identified facilities. Reduced dimensions and
modern technology result in a lighter and less bulky machine than the
Teleprinter No. 15. Other features include a rotating
print wheel and ink roller cassette replacing the conventional
type basket and ribbon. It is modern in appearance and
comes complete with its own pedestal.
3 FACILITIES
Some of the facilities of the Teleprinter No. 23 are
described in detail below:-
3.1 Automatic Insertion of Figure Shift and Letter
Shift
The automatic insertion of figure shift and letter shift obviates the need
to operate separate figure shift and letter shift keys
during normal operation. Although this automatic
facility is provided, letter shift (A...) and figures shift (1...) are still
included on the keyboard layout. These allow the case shift codes to be sent
independently, if necessary.
3.2 New Line Key (Combined carriage return line feed)
On the right hand side of the keyboard is a large key
shaped like a reverse 'L' engraved with the symbol ...1. This is the new
line key (combined carriage return line feed).
3.3 Tape Edit
Although tape edit is not a new facility it is
achieved more simply on the Teleprinter No. 23 by use of the 'Step' and 'Skip'
keys. Each depression of the 'Step' key allows one character of an existing
tape to be transmitted to line or punched onto a new tape.
Similarly one depression of the 'Skip' key prevents
the transmission to line or punching on a new tape of one
character thus allowing the existing tape to pass freely through the reader;
a new character can then be inserted from the keyboard as required.
3.4 Underline of Outgoing Message
The ink roller which replaces the conventional ribbon is only available in
one colour. To enable users to identify an outgoing
message from an incoming one, the Teleprinter No. 23 has an 'underline'
facility. The first four characters of each
line of transmitted text, and any under copies, are
underlined.
3.5 Shift Keys
Some of the figures keys have two characters engraved
on them e.g. the key for '3' also has '£'. The upper character can be typed
only when the shift key is operated simultaneously. This is similar
to the operation on a typewriter, except that the shift key
is non-locking.
3.6 Tape Preparation
The tape preparation sequence on the Teleprinter No. 23 is the same as on
the Teleprinter No. 15. However an incoming call to the Teleprinter 23 will
lock the keyboard until the 'reset' button is pressed. This obviates
corruption of existing copy and/or tape. A particularly useful feature of
the Teleprinter 23 is that a tape may be prepared while another is being
transmitted. Once a call is established and text transmission is in
progress, depression of the 'local' key will allow preparation of a new
tape. Local copy of the new tape only will be printed and users will need to
ensure that transmitted text has been received by seeking the answerback
code of the distant teleprinter.
3.7 Line Feed Option and Incoming Call Alarm Switches
Under a flap on the front right hand side of the Teleprinter 23 is a panel
of three switches. Two are functional, the other is spare. The line feed
switch offers a choice of two spacings, viz single or double. The incoming
call alarm switch offers an on/off option. Both are customer controlled.
4 PEDESTAL
The Teleprinter 23 is provided with a pedestal. Customers who
do not require a pedestal must provide a suitable alternative means
of support. The customer will be liable for any damage caused through
failure to comply with this condition.
There is no tariff reduction should the customer decide
not to have a British Telecom pedestal.
5 MARKETING
5.1 Telex
The Teleprinter 23B/50 is now the standard teleprinter on telex. If,
however, a customer insists on being provided with a teleprinter without
automatic transmission facilities, Teleprinter No. 15 Basic may be offered.
Similarly, if for historic reasons, or in the interests of avoiding the
problems associated with operations with two different models of teleprinter, at the insistence of the customer a Teleprinter 15 Auto may be
offered.
5.2 Private Telegraphs
Teleprinter No. 23B/75 is now the standard BT teleprinter for use on new or
existing point-to-point Tariff H or J private telegraph circuits, or as
terminals on privately supplied message switcher or BT supplied PATX1A or
PATBX2A.
5.3 Availability
Both Teleprinters No. 233/50 and 233/75 are nationally available. The small
stock of factory made 23B/75's is now exhausted and future supply will be met
by conversion of 23B/50s by Area Telegraph Workshop, for which Work
Specification No. TG4462 is available.
5.4 Off-Line Machine
Requests for off-line machines for message preparation should be met by
Teleprinter No. 23B/50.
6 SELLING BENEFITS
The selling benefits of the Teleprinter No. 23 are identified as follows:-
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Smaller and lighter than existing full facility
teleprinters.
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Electronic components make it reliable and relatively
easier to maintain.
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The keyboard closely resembles that of an electric
typewriter making it easier for typists to operate.
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Its ink roller lasts longer and is easier, cleaner
and quicker to replace than the conventional ink ribbon.
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The underline facility allows easy identification of
incoming and out-going messages on original and undercopies.
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Automatic figure/letter shift.
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New line key combining carriage return/line feed.
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Its seven character keyboard store accommodates fast
bursts of typing.
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The improved tape edit facility allows previously
prepared tape to be updated or amended more easily.
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A new tape may be prepared while another is being
transmitted,
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It has the capability to accept an incoming call
automatically if the Teleprinter is being operated in local, without
corruption of the hard copy.
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Visual and audible alarms for tight tape.
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Incoming call alarm option.
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Single or double line feed option.
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Multiple copies (1+3).
7 DIMENSIONS
Width 528mm (22")
Depth 572mm (22.5")
Height 910mm (35.5") With pedestal (260mm without pedestal)
Weight 42kg (approx. 93lbs) With pedestal (31kg approx. 68lbs without
pedestal)
Made by ITT Creed Ltd.
POEEJ
Article on the Teleprinter No. 23
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