LINK Systems LinkNet II - Manual (Page 12)

Belden 8103 cable and many similar cables organized as twisted pairs use a special color code
scheme. Instead of each wire using a different color, each pair uses a color. One wire in the pair is
predominately white with a thin color stripe, and the other wire in the pair is predominately the color
with a thin white stripe. When referring to these wires a common convention names the predominate
color first. For example, a blue wire with a thin white stripe is called blue with white (shortened to
blue/white). A white wire with a thin blue stripe is called white with blue (shortened to white/blue).
This convention will be used in this document.
Other wire types can be used, but assuming Belden 8103 cable and the Link RS232 to RS485
converter, the network should be wired as shown in the following sections.
2.1 RS232-RS485 Converter Network Connections
The Link converter is labeled the same way as network drop boxes on the RS485 side. The RS232
side is equipped with a 6' cable that plugs into any standard 9-pin serial port connector on the host
computer. A power cord is also provided. The six terminal RS485 connector should be wired as
follows:
GND
- Green/White and White/Green
RXD+ - Orange/White
RXD- - White/Orange
TXD+
- Blue/White
TXD- - White/Blue
SHLD
- Shield (bare) Wire of Cable
Although not recommended, if another kind of RS-232 to RS-485 converter is used, it should be set
up in the following manner:
1) If configurable, transmit should always be on.
2) TX+ should connect to RXD+ on the drop box (Orange/White wire).
3) TX- should connect to RXD- on the drop box (White/Orange wire).
4) RX+ should connect to TXD+ on the drop box (Blue/White wire).
5) RX- should connect to TXD- on the drop box (White/Blue wire).
Note that “RX” and “TX” can be called different things depending on the manufacturer of the
converter, but will usually reflect some variation of “transmit” and “receive” (such as TXD and RXD).
2.2 Drop Box Network Connections
There are two kinds of drop boxes, regular and repeater. Regular drop boxes (Figure 2.2) simply
have connectors for field wiring to pass through the communication signals. Repeater drop boxes
(Figure 2.3) have active circuitry in addition to the terminals the regular drop box has. This circuitry
allows the network to extend over 4000ft and can allow more than 32 units to be attached to the line.
Drop boxes have three sets of plugable terminal strips labeled “DATA IN”, “DATA OUT”, and
“UNIT”. The terminal strip labeled “DATA IN” should be connected to the wire coming from the host
computer side, “DATA OUT” should go to the next drop box, and “UNIT” should go to the Link
equipment on the press.
Manual Version 1.1 10/28/2001 2.2