Mita DP-2800 Instruction Handbook Manual page 122

The Manual Select jumper allows the user to force the EcoLAN 1000E to operate
from the indicated connector. Note that with the Manual-10BaseT connection, the
card will operate 10BaseT without the support of the LINK connect signal.
The Collision Threshold jumper is for Thinnet interfaces only. The 10BaseT Ethernet
interface does not use this jumper. The default setting is Transmit Threshold (jumper
adjacent to panel). You may wish to change this jumper to Receive Threshold if you
are using the Thinnet interface and you wish to adjust the collision threshold.
Jumper Settings Appendix A- 4