Eiki NPC-1 - Manual (Page 23)

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Cable Pinouts
RS232
RS232 standards are defined by EIA/TIA (Electronic Industries Alliance /Telecommunica-
tions Industry Association). RS232 defines both the physical and electrical characteristics
of the interface. RS232 is practically identical to ITU V.24 and V.28 (electrical). RS232 is
an Active LOW voltage driven interface and operates at +12V to -12V where:
Signal = 0 (LOW) > +3.0V
Signal = 1 (HIGH) < -3.0V
Signal voltages in the range >-3.0V to +3.0V is regarded as the 'dead area' and allows for
absorption of noise.
Please watch carefully the terms DTE (Data Terminal Equipment - e.g. a terminal or PC)
and DCE (Data communications Equipment - e.g. a modem) the meaning and use of
certain pins may differ. The diagrams below define the interface from the DTE perspec-
tive. The NPC-1 has a RS232 DTE connection.
RS232 on DB9 (EIA/TIA 574)
Pin No. Description
1 DCD, Data Carrier Detect
2 RxD, Receive Data
3 TxD, Transmit Data
4 DTR, Data Terminal Ready
5 GND, Ground
6 DSR, Data Set Ready
7 RTS, Request To Send
8 CTS, Clear To Send
9 RI, Ring Indicator
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