Nortel Networks Video Gaming Accessories 553-3001-211 Manual De Usuario

Appendix A: LAPB Data Link Control protocol

LAPB subset of the HDLC protocol and transmitted serially to the line at a 
rate determined by the downloaded parameters.

The QPC513 card receives data serially from the line, packaged in LAPB 
information frames. After determining that a block is error free the data is 
supplied to the Circuit Switch Equipment as a block.

All transmissions are in frames and each frame conforms to the format shown 
in Table 275 on 

. In particular, frame elements for applications using 

a port on the QPC513 follow these LAPB conventions:

•

Zero information field is permitted.

•

Inter-frame time fill is accomplished by transmitting contiguous flags. 
This is compatible with AT&T Technical Requirement BX.25 and 
ADCCP standards.

•

Extensions for the address field or the control field are not permitted. 
This requirement imposes constraints to satellite operations.

•

Individual station addresses are assigned in service change for balanced 
configuration. The default ESDI address is 10000000. The far-end 
default address is 11000000.

•

The LAPB basic control field (modules 8) format is implemented.

•

Frame check sequence is implemented in accordance with LAPB 
procedures.