  
Part 3: I/O Port Pinouts
Topics:
I/O Port Pinouts
The EasyConnection modules house female DB25
sockets or RJ45 female connectors. The port numbers are marked
near their respective sockets on the module.
Cabling Issues
Serial devices may be attached to EasyConnection
boards in various module configurations. The modules available
are:
- 8 port DB25 module (RS-232)
- 16 port DB25 module (RS-232)
- 8 port RJ45 module (RS-232)
- 16 port RJ45 module (RS-232)
- 8 port DB25 dual interface module
(RS-232, RS-422 and RS-485)
As additional serial ports are required, more
can be added by simply attaching extra modules, allowing 8 to
64 ports per slot.
Serial Interfaces
for Asynchronous Modules
All asynchronous modules support RS-232-D signalling.
The enhanced standard removes the once imposed 50ft distance limit,
though in practice, reliable operation was possible over 100 feet (30
metres) using low capacitance cable.
Using very low capacitance cable (5 pF/foot)
with EasyConnection means that reliable RS-232 operation is possible
up to 500 feet (150 metres) at data rates up to 38.4 Kbps. This
assumes that the system and the serial device are in the same building
and that there is a chassis ground connection between the devices through
the cable shielding.
For medium speed devices which are up to 4000
feet (1220 metres) from the host system, the Dual Interface Module should
be used as it offers balanced RS-422-A and RS-485 operation as well
as RS-232. The user can choose any of these standards on any port
by simply wiring the cable for that standard.
Standard Module.
EasyConnection uses RS-232 low-power ICs with high noise immunity and
can drive data rates up to 145 Kbps over very low capacitance cable
to 100ft (30 metres) . In many instances, this eliminates the
need for a short haul modem or having to use RS-422-A converters for
the serial device.
XP Module.
The XP (Extra Performance) module incorporates UARTs capable of supporting
serial speeds of 230,400 and 460,800 baud. The DB25 pinout of the XP
module is identical to the standard module. Note however, that cable
lengths must conform to limits in the RS-232 specification. The high
speed capability is provided for the purpose of connecting high speed
devices such as Terminal Adapters over short cable distances (ie. up
to 3 meters). The XP module may be used with all EasyConnection
host adapters and other module types and is supported by Rev 5.3 or
later software drivers.
Asynchronous
Module DB25 Pinout (DTE)
Asynchronous Module DB25
Pinout (DB25 Pinout RS-232):
| 1 |
Chassis GND |
|
| 2 |
TXD |
| 3 |
RXD |
| 4 |
RTS |
| 5 |
CTS |
| 7 |
Signal GND |
| 8 |
DCD |
| 20 |
DTR |
Asynchronous
Module RJ45 Pinout (DTE)
Asynchronous Module RJ45 Pinout (RS-232):
Note:
The 8 pin RJ45 female connector also mates with RJ11 and RJ12 males.
The RJ11 has four pins and will connect with pins 3-6 on the RJ45. The
RJ12 has six pins and connects with pins 2-7 on the RJ45.
For software handshaking you can use any RJ
connector. For hardware handshaking you must use an RJ12 or RJ45
connector. For modems using all of the above lines, you must use
an RJ45 connector with 8 pins.
Dual Interface Module
DB25 Pinout
Dual Interface Module
DB25 Pinout (RS-232, RS-422 & RS-485)
| 1 |
Chassis GND |
|
| 2 |
TXD |
| 3 |
RXD |
| 4 |
RTS |
| 5 |
CTS |
| 6 |
DSR* |
| 7 |
Signal GND |
| 8 |
DCD |
| 15 |
R(B) or RX+ |
| 17 |
R(A) or RX- |
| 18 |
CONV |
| 19 |
T(B) or TX+ |
| 20 |
DTR |
| 25 |
T(A) or TX- |
Cabling Diagrams
This section illustrates common RS-232, RS-422
and RS-485 cabling.
Common RS-232 Cables
The following section shows common wiring configurations
for both DB25 and RJ45 connectors.
Asynchronous Modem
Cable
Software Handshaking
Cable (3 Wire)
Hardware Handshaking
Cable (Wyse 60 Terminal)
Standard PC COM Port
to EasyConnection Port
EasyConnection Port
to EasyConnection Port
Software Handshaking
Printer Cable
Most printers use software handshaking (XON-XOFF). This cable should
work with most printers.
Hardware Handshaking
Printer Cable
Note:
If the terminal or printer does not use DTR (pin 20) to indicate a busy
condition, substitute the correct signal on the correct pin for DTR
(pin 20) on the terminal or printer end in the above diagrams. Some
printers also need either or both of the signals DSR and DCD to be held
high to enable the printer to receive data. This can be achieved by
linking DCD and DSR to another signal on the printer, such as DTR or
RTS. Make sure this signal is not used as the hardware handshaking signal.
Wyse-60 Attached Printer
Cable
RS-422 Cable
When running diagnostics on a panel that is
configured for RS-422A, the loopback plug supplied with the dual interface
module should be used. For outdoor installations, an extra surge protection
device should be connected at both ends of the cable to guard against
induced high voltages (i.e lightning). Damage caused by incorrect wiring
or induced voltages is not covered by Stallion's warranty.
RS-485 Cable
RS-485 is an upgraded version of RS-422-A, using
the same signal levels but extending the number of peripherals that
a computer can interface to. Additionally, RS-485 allows for bi-directional
multi-point party line communication and can effectively be used for
"mini-LAN" applications eg. between point of sale terminals and a central
computer.
A 2 wire party line port is wired as follows:
The EasyConnection port may be one of up to
32 transmitters and 32 receivers connected to a 2 wire differential
pair.
Note: Cabling
and bus termination must conform to EIA RS-485 standard.
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