PCI MUX Cabling Solutions

The AD279A solution can support up to four 16-port RS-232 port modules. The port modules provide
either DB25 Male RS-232 serial ports or RJ45 RS-232 serial ports.
Pin-Layout and Port Interface Differences between A6748A/A6749A
and AD278A/AD279A PCI MUX Serial Ports
Table 5 describes the pin-layout differences between A6748A/A6749A and AD278A/AD279A PCI
MUX serial ports.
Table 5: A6748A/9A and AD278A/9A RJ45 RS232 Pin-Layout Comparison
AD278A / AD279A Serial MUX
Solution
A6748A/A6749A Serial MUX
Solution
Interface type RJ 45 RS 232 ports RJ 45 RS 232 ports
Pin # 1 RI Ring Indicator RI Ring Indicator
Pin # 2 DSR Data Set
Ready
RTS Request to
Send
Pin # 3 RTS Request to
Send
DTR Data Terminal
Ready
Pin # 4 GND Chassis
Ground
RXD Received Data
Pin # 5 TXD Transmitted
Data
GND Ground
Pin # 6 RXD Received Data TXD Transmitted
Data
Pin # 7 SG Signal Ground GND Signal Ground
Pin # 8 CTS Clear to Send DCD Data Carrier
Detect
Pin # 9 DTR Data Terminal
Ready
CTS Clear to Send
Pin # 10 DCD Data Carrier
Detect
DSR Data Set
Ready
The AD278A/AD279A PCI MUX solution provides Male DB25 RS-232 serial ports, whereas the
A6748A/A6749A PCI MUX solution provides Female DB25 RS-232 serial ports. The DB25 pin-outs
for the AD278A/AD279A PCI MUX solution and A6748A/A6749A PCI MUX solution are the same.
Cabling Cases and Solutions
This section discusses instances of incompatibility between A6748A/A6749A and
AD278A/AD279A PCI MUX solutions. It also discusses solutions to resolve these incompatibilities.
Table 6 lists scenarios of incompatibility that prevent successful migration from A6748A 8-port RJ45
solution to the AD278A/AD279A PCI MUX solution. It also describes methods to resolve issues of
incompatibility.