Black Box ME540A-ST, Manual, Page: 11 / 26

FOM LINE DRIVER—ST AND S M
1 0
Fiberoptic Cable Connections
Because of the subtleties of the various modes of operation, review
Chapter 3, Configurations
, for the
proper inter-unit connections.
If you chose XW2A (RS-232) as your interface selection, go to
Section 4.2
. If you chose XW2B (RS-485)
as your interface selection, go to
Section 4.3
. If you chose XW2C (20-mA current loop) as your interface
selection, go to
Section 4.4
.
4.2 RS-232
Follow these instructions to set up the RS-232 interface.
1.
Set XW1.
XW1A sets the Driver for DCE. XW1B sets the Driver for DTE.
XW1A ------DCE*
XW1B ------DTE
DB9 Pinouts
DCE DTE
2—TX Data 2—RX Data
3—RX Data 3—TX Data
7—RTS Input 7—RTS Held High
4—DTR Input 4—DTR Held High
8—CTS Output 5—Signal Ground
6—DSR Held High 8—No Connect
1—CD Held High 6—No Connect
5—Signal Ground 1—No Connect
2.
Set W3.
If you selected XW1A (DCE), Position AB will enable DTR (DTR controls CTS). In position
BC, RTS controls CTS. If you selected XW1B (DTE), all handshake leads are ignored, and W3 will
have no effect. It’s not necessary to set W3.
If XW1A was selected, Position AB ------DTR*
or
If XW1A was selected, Position BC ------RTS loops back to raise CTS
or
If XW1B was selected, W3 has no effect.
3.
Set W2.
W2 sets the delay of CTS assertion with the raising of DTR or RTS. 0 means there will be no
delay. 10 gives you a 10-millisecond delay, and 30 is a 30-millisecond delay.
0------------No delay
10----------10-msec. delay
30----------30-msec. delay
*Factory default.