| Passthru
connects inputs to outputs without regeneration. Both S1 and
S2 must be set to passthru. Note for 239TP: Low signal may not
make it to the next apparatus case.
T/R Short
connects tip and ring for far end continuity tests.
Open, straight
test pins; no connection to other pins.
Loopback
connects four-wire circuit back toward originating direction
without regeneration. Note for 239TP: This is an illegal state
for a unindirectional span (this signal is not regenerated). |
