AMX Modula Instruction Manual page 148

RS-422 Boards
Termination Jumper
Typically jumper pins for a connector should be set for termination when high data rates or long cable
lines are used. Each connector has two 100-ohm, 3-pin jumpers. The jumper needing termination
depends on the toggle switch setting (see the table below). The board must be removed to access the
jumpers (for instructions on removing and replacing a board, see "Appendix D – Adding or Replacing
Boards" on page 171). The factory default setting is "not terminated," as indicated in FIG. 99 on the left
(J1 and J2 jumpers are each on Pins 2 and 3, the unnumbered pins).
To terminate a jumper pin (provide a termination load):
1.
Move the jumper to cover Pin 1 (numbered) and Pin 2, as indicated in FIG. 99 on the right.
J1 – Not Terminated
J2 – Not Terminated
FIG. 99
Example: Terminate J1 jumper (cover Pins 1 & 2) when first connector is set to CTL
The table below shows which jumper to terminate depending on the toggle switch setting for the port
configuration type (to determine switch settings, see page 141
Termination Jumper Settings
First Connector
Second Connector
Third Connector
Fourth Connector
142
Switch set to CTL (controller)
J1 – Terminated
J2 – Not Terminated
Switch Set to CTL (Controller)
Terminate J1
Terminate J4
Terminate J6
Terminate J8
page 178
).
Switch Set to DEV (Device)
Terminate J2
Terminate J3
Terminate J5
Terminate J7
Modula Instruction Manual