Denso BHT-400B-CE - Manual (Page 163)

Chapter 5 Handling the CU-400 (Option)
5.4.2 Interface Cable Connection
(1) Unplug the AC adapter of the CU-400 from the wall socket.
(2) Make sure that the host PC is turned off.
(3) CU-401: Connect the RS-232C interface cable to the interface port of the CU-401.
CU-421: Connect the USB interface cable to the interface port of the CU-421.
Interface cable
CU-401: RS-232C
CU-421: USB
(4) Connect the other end of the RS-232C/USB interface cable to the corresponding port of the host PC.
TIP: The CU-421 can be connected via a USB hub to the host PC.
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