DeviceMaster Primo Hardware Installation
9
Building (RS-232) Null-Modem Cables
Building (RS-232)
Null-Modem Cables
Use the following figure if you need to build a null-modem cable. A null-modem
cable is required for connecting DTE devices.
Note:
You may want to purchase or build a straight-through cable and purchase a
null-modem adapter.
Building RS-422
Null-Modem Cables
Use the following figure if you need to build an RS-422 null-modem cable. A null-
modem cable is required for connecting DTE devices. Make sure that you use
twisted-pair cable.
Building RS-232
Straight-Through
Cables
Use the following figure if you need to build an RS-232 straight-through cable.
Straight-through cables are used to connect modems and other DCE devices.
TxD
RxD
RTS
CTS
DSR
GND
DCD
DTR
Signal
RxD
TxD
CTS
RTS
DTR
GND
DCD
DSR
Signal
DB9
2
3
8
7
4
5
1
6
Pins
Dev
iceMa
ster Pri
m
o
RI
9
RI
DB9
3
2
7
8
6
5
1
4
Pins
9
DB25
3
2
4
7
8
6
Pins
20
5
22
Primo
RXDA+
TXDA+
Signal
3
2
Pins
TXDB-
1
RXDB-
4
Data Terminal
DB9
TXDA+
RXDA+
Device
RXDB-
TXDB-
RTSA+
RTSB-
GND
CTSA+
Optional connections for signal ground and
hardware flow control:
7
6
5
8
CTSB-
9
CTSA+
CTSB-
GND
RTSA+
RTSB-
De
vic
eMaster Primo
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD
DTR
GND
CTS
DSR
RTS
Signal
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD
DTR
GND
CTS
DSR
RTS
Signal
RI
9
9
RI
DB25
8
3
2
20
7
5
6
4
Pins
22
