6100 ADCCP Programming Manual

6100 ADCCP Concepts and Context
Introduction to 6100 ADCCP
1–12 069225 Tandem Computers Incorporated
The control field is 1 byte long but can be 2 bytes long in extended control. Figure 1-7
shows the different formats of the control field; the direction of transmission is to the
left.
Figure 1-7. Control-Field Formats
005
Information
Frame
01234587
0 Ns P/F Nr
LSB MSB LSB MSB
Supervisory
Frame
1 S P/F Nr
LSB MSB
0 S
0 Ns
LSB MSB
0123456789101112131415
P/F
Nr
LSB MSB
1 P/F Nr
LSB MSB
0SS0000
Unnumbered
Frame
Ns
Nr
LSB
MSB
= Number Sent Variable
= Number Received Variable
= Least Significant Bit
= Most Significant Bit
S
U
P/F
= Supervisory Message Encoding
= Unnumbered Message Encoding
= Poll/Final Bit Position
1 U P/F1 U UU U 1 1 U U P/F U U U P/F0000000
Basic 1-Byte Format
(HDLC, SDLC, ADCCP)
Extended 2-Byte Format
(ADCCP)
First Byte Second Byte
Legend
01234587
012345678910111213141501234587
0123456789101112131415