Configuring Serial Signal Polarities
Serial interfaces use a differential protocol signaling technique. Of the two serial signals associated with a circuit, the one referred to as the A signal is denoted with a plus sign, and the one referred to as the B signal is denoted with a minus sign; for example, DTR+ and DTR–. If DTR is low, then DTR+ is negative with respect to DTR–. If DTR is high, then DTR+ is positive with respect to DTR–.
By default, all signal polarities are positive. You can reverse this polarity on a Juniper Networks serial interface. You might need to do this if signals are miswired as a result of reversed polarities.
For EIA-530 and V.35 interfaces, configure signal polarities by including the cts-polarity, dcd-polarity, dsr-polarity, dtr-polarity, rts-polarity, and tm-polarity statements:
You can include these statements at the following hierarchy levels:
- [edit interfaces se-pim/0/port serial-options]
- [edit interfaces se-fpc/pic/port serial-options]
For X.21 interfaces, configure signal polarities by including the control-polarity and indication-polarity statements:
You can include these statements at the following hierarchy levels:
- [edit interfaces se-pim/0/port serial-options]
- [edit interfaces se-fpc/pic/port serial-options]
