IRM3 User’s Guide
Page A-1
APPENDIX A
SPECIFICATIONS
The operating specifications for Cabletron Systems IRM3 are included in
this Appendix. Cabletron Systems reserves the right to change these
specifications at any time without notice.
A.1 REPEATER FUNCTIONALITY
Delay Times (Port x In to Port x Out):
Start of Packet:
1450 ns maximum.
Collision to JAM:
1550 ns maximum.
Preamble:
Input:
Minimum of 40 bits to a maximum
of 64 bits required.
Output:
64 bits minimum (last 2 bits are 1,
1).
JAM Output:
If a collision occurs on one of the
segments, a pattern of 1, 0 is sent to
the other segments.
Minimum Packet Repeated:
96 bits including preamble (packet
fragments are extended using the
JAM [1, 0] data pattern).
FAULT Protection:
Each segment disconnects itself
from the other segments if 32
consecutive collisions occur, or if
the segment’s collision detector is
on for longer than approximately
2.4 ms. This FAULT protection
resets automatically after a packet
is transmitted onto the FAULT
protected segment without causing
a collision.