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Details of the Packet Format for the X.25 Packets used in call establishment and call clearing are provided in this section. It describes the fields that must be filled by the application.
The format for a Call Request Packet is shown below. Octets consist of bits numbered 7 to 0 where bit 0 is the low order bit and is transmitted first. Octets are consecutively numbered starting from 1 and are transmitted in this order. See the CCITT X.25 Recommendation for details.
*Semi-octet of zeroes is present only if combined total digits in DTE address block is odd
The first three octets (up to and including Packet Type Identifier) are handled by the Eicon X.25 Development Kit. The rest of the octets are built from information supplied by the application program.
The format for a Call Accepted Packet is shown below. Octets consist of bits numbered 7 to 0 where bit 0 is the low order bit and is transmitted first. Octets are consecutively numbered starting from 1 and are transmitted in this order. The General Format Identifier can be coded 0x01 for modulo 8 or to 0x10 for modulo 128. See the CCITT X.25 Recommendation for details.
*Semi-octet of zeroes is present only if combined total digits in DTE address block is odd
The first three octets (up to and including Packet Type Identifier) are handled by the Eicon X.25 Development Kit. The rest of the octets are built from information supplied by the application program.
The format for a Clear Request Packet is shown below. Octets consist of bits numbered 7 to 0 where bit 0 is the low order bit and is transmitted first. Octets are consecutively numbered starting from 1 and are transmitted in this order. The General Format Identifier can be coded 0001 for modulo 8 or to 0010 for modulo 128. See the CCITT X.25 Recommendation for details.
*Semi-octet of zeroes is present only if combined total digits in DTE address block is odd
The first three octets (up to and including Packet Type Identifier) are handled by the Eicon X.25 Development Kit. The rest of the octets are built from information supplied by the application program.
The format for a Clear Confirmation Packet is shown below. Octets consist of bits numbered 7 to 0 where bit 0 is the low order bit and is transmitted first. Octets are consecutively numbered starting from 1 and are transmitted in this order. The General Format Identifier can be coded 0001 for modulo 8 or to 0010 for modulo 128. See the CCITT X.25 Recommendation for details.
*Semi-octet of zeroes is present only if combined total digits in DTE address block is odd
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Copyright (c) 2001 Eicon Networks