Received copy with typical identification

CCITT NSF signals

Messages on the transmitted facsimile page

Numeric, alphanumeric or graphical messages held in a transmit memory and sent as part of the facsimile transmission. They are not sent in T.30 format. Because they are facsimile encoded the receive machine remains ignorant of the content and cannot record them in the reports. The information may contain:

1. Document number, time and date of sending.

2. Sender's name or TSI.

3. Urgent or priority comment.

Although the implementation may be proprietary to the manufac­ture it is printed on all receivers because it is included in the facsimile message. It is often transmitted outside the regular A4 page increasing the received page length.

Under the non standard facilities procedure a manufacturer may implement any proprietary identification form desired. When trans­mitting to another machine of the same manufacturer it may include alpha as well as numeric characters. This can enable the name of the communicating machine to be shown on the display or recorded in the activity report. It is not recognised between machines of differ­ent manufacturers.

NSF covers a wide range of proprietary features but in the ident­ification area it also allows the transmission of passwords for confidential operation.

In addition to the text at the top (date, time and sender identification) transmitted as part of the facsimile image, other information, com­piled at the receiver from the transmitted TSI/NSS and from locally available information in the receiver, may be added.

The word 'END' is sometimes inserted at the bottom of the facsimile image to confirm that this is the last page of the document.

60.5 64kbit/s facsimile equipment

The availability of switched digital networks with 64kbit/s channels continues to increase with basic rate and primary rate ISDN. The I Series recommendations developed by CCITT have established international standards for 64kbit/s intercommunication.

The G3 transmissions use the voice speech band which, when converted to PCM digital signals for transmission within the public network, use the complete 64kbit/s channel. This means 9.6kbit/s or 14.4kbit/s maximum rate on a 64kbit/s channel.

Clearly where 64kbit/s digital access is available, as through the ISDN connection, a direct digital input at 64kbit/s machine data rate is desirable giving an improvement of four to six times in speed and reduction in transmission cost. To take advantage of this a 64kbit/s data rate facsimile machine is required.

Дата добавления: 2015-03-31