IBM PC MMX Pentium HS-4500, Manual, Page: 23 / 51

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The HS-4500 also provides for user in select to using the COM4 as an
RS-232/422/485. The CN18 for uses as an RS232, the CN11 for uses as
an RS422 or RS485.
Please reference to the following for setting the JP9 & JP11 at disable
and JP6 at enable if uses as RS232 at CN18. Or setting the JP9 & JP11
at non-disable and JP6 at disable if uses as RS422 or RS485 at CN11.
The default setting is RS-232 at CN18.
z
CN11 : RS422/485
PIN NO. DESCRIPTION PIN NO. DESCRIPTION
1 TX- 2 TX+
3 RX+ 4 RX-
5 GND 6 RTS-
7 RTS+ 8 CTS+
9 CTS- 10 NC
z
JP9 : Receiver Enable Control
JP9 DESCRIPTION
1-2 ON Always Enable
3-4 ON Enable by writing the REG : 2 EFH BIT1=1
*1-2 OFF Always Disable
z
JP11 : Transceiver Enable Control
JP11 DESCRIPTION
1-2 ON Always Enable
3-4 ON Enable by ”-RTS” signal
5-6 ON Enable by writing the REG : 2 EFH BIT0=1
*7-8 OFF Always Disable
z
JP6 : COM4 Selection
JP6 DESCRIPTION
ON Disable
*OFF Enable
*) : default setting