3.0 CONFIGURATION
The Model 2017P is designed to be easy to use. There are no
internal jumpers or DIP switches to set, so there is no need to open the
case to configure the unit (you may need to open the case for wire
connection—refer to Section 4.0). The only configuration necessary for
operation is proper setting of the external DCE/DTE switch.
The diagram below shows the location of the DCE/DTE switch on
the PC board, as well as the location of the terminal block and surge
suppressors ("S" model only).
3.1 SETTING THE DCE/DTE SWITCH
For your convenience, the Model 2017P has an externally
accessible DCE/DTE switch (see diagram below). If the RS-232 device
connected to the Model 2017P is a modem or multiplexer (or is wired
like one), set the switch to "DTE". This setting causes the Model 2017P
to behave like Data Terminal Equipment and transmit data on pin 2.
If the RS-232 device connected to the Model 2017P is a PC,
terminal or host computer (or is wired like one), set the switch to "DCE".
This setting causes the Model 2017P to behave like Data
Communications Equipment and transmit data on pin 3.
4
3
4.0 INSTALLATION
The Model 2017P is simple to install. After configuring the
DTE/DCE switch, connect the two twisted pairs using one of three
methods: terminal blocks with strain relief, RJ-11 jack or RJ-45 jack.
The method you use will depend on the specific model you have.
4.1 TWISTED PAIR WIRING OVERVIEW
Only one Model 2017P is needed for each RS-232 to 20mA (or
60mA) current loop circuit. The Model 2017P is connected to the
current loop device using two twisted pairs. The pairs must be "dry"
(unconditioned) metallic wire, 19 - 26 AWG. Best distance is achieved
with larger gauges. When you have completed wiring for your data
circuit, the pin connections should be as shown below:
4.1.1 TWISTED PAIR CONNECTION USING TERMINAL BLOCKS
The terminal block/strain relief version of the Model 2017P allows
you to hook up the line side interface using bare wires. The following
instructions will tell you how to open the case, connect the bare wires
and fasten the strain relief collar in place.
1. Open the unit by gently inserting a screw driver between the
DB-25 connector and the lip of the plastic case (see below). You don't
have to worry about breaking the plastic, but be careful not to bend the
D-sub connector.
DCE/DTE
Switch
Terminal
Block
Opto
Isolator
Opto
Isolator
XMT +
RCV+
XMT -
RCV -
G
G
RCV +
XMT +
RCV -
XMT -
To Shield (Optional)
}
One Pair
}
One Pair
DCE
DTE
