Hitachi H Series Instruction Manual page 143

Chapter4 Loop back check
Carry out the following loop back check using a dip switch (see 1.2 ⑦)
Check the circuits of transfer systems in module units.
Connect a TxD connector and an RxD connector together and set the dip switch in the ON
position. The result of the check can be observed by the "ERR" LED.
- Set the check switch in the ON position, connect TxD and RxD together by means of
a cable for check and turn ON the power. A loop back check is conducted.
- In the normal state, check is continued while the loop back data is updated, until the
power is OFF.
- The ERR LED lights up on occurrence of an error.
Notify our service department of it in this case.
Be sure to return the check switch to the "OFF" position on termination of the loop
back check.
Besides, in detail as occasion demands please see the instruction
manual of LINK-H (NB962*(X): separate account) or OLINK-H
(NB977*(X): separate account).
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