60.2.5 Government and military equipment

Similar requirements exist for the transmission of documents, maps, drawings, photographs etc. as in other market segments. One major difference is that for the transmission of documents classified for national security, additional high performance data encryption equipment is required. Further, to avoid plain language signals from the fax equipment itself being intercepted, and to avoid compromi­sing the encryption key generator codes, significant precautions must be taken in equipment design to reduce the relevant radiated and conductive electromagnetic emissions. These security require­ments are not normally published.

60.2.5.1 Strategic requirements

These machines normally operate in regular office environments and apart from interoperational requirements for secure fax or tactical machines, communication can usually be met by standard CCITT G3 models.

60.2.5.2 Tactical requirements

Machines for this use include military battlefield equipment to operate under inhospitable environmental conditions, fast, reliably and securely. Standards are desirable to ensure interoperation be­tween allies of different national forces. Typical features of the NATO standard are:

1. Up to 16 grey shades for photographs.

2. G3 standard and fine resolution equivalents.

3. Broadcast and duplex network operations.

1. G3 MH compression, also uncompressed and BCH forward error correction.

To be acceptable this equipment should be lightweight, easy to operate in arduous conditions and capable of various communica­tion modes, including high speed burst mode to avoid radio location when necessary.

60.3 Ccitt document facsimile equipment

This is principally for the transmission of business and commercial papers, letters, drawings and general office documentation around A4 size (21()mm x 297mm). The pages are often black or dark coloured text or handwritten characters on white or pastel back­grounds, although machines handle a wide range of original docu­ments.

CCITT has produced and continues to develop recommendations for operation on the public telephone and public data networks, which are summarised in Table 60.2.

1 Learn the words & word combinations:

Pendulum scanner	Маятниковый сканер
exposure	фотосъемка
dotted structure	точечная структура
Claim	Требования
Exceed	Превышать
interworking	организация межсетевого взаимодействия
Confirmation	Подтверждение
operating costs	эксплуатационные расходы
Demand	Требовать
thermal (thermosensitive) paper	термочувствительная бумага, термографическая бумага
Preserve	Сохранять
transceiver	приемопередатчик
Achieve	Достигать
aspect ratio	формат изображения, формат кадра
Savings	Сбережения
color separation	цветоделение
Opinions	Мнения
distribution network	распределительная сеть
workstation	автоматизированное рабочее место
application layer	прикладной уровень, уровень приложения
monochrome image	монохроматическое (одноцветное) изображение
image scanner	сканер изображения
weatherfax	факс для передачи метеорологических карт
raw data	исходные данные, необработанные (предварительные) данные
reproduction radio	масштаб съемки при репродуцировании
mobile equipment	передвижное оборудование
data encryption	шифровка данных
plain language	упрощенный язык
encryption key	ключ шифрования
radiated emission	излучение
fine resolution	высокая разрешающая способность
forward error correction	прямое исправление ошибок (без повторной передачи)
burst mode	режим ускоренной обработки, режим пульсирующего трафика
carbon paper	копировальная бумага

2 Find Russian equivalents:

at the same cost	the desired aim
power source	equipment purchase price
point to multipoint computer data transfer	speech band private circuit
private circuits raw data	correct aspect ratio cellular radio system
sophisticated high speed transmission developments	performance data encryption equipments
synchronous transparent channel arduous conditions	large G3 installed base