Serial Interface; Serial Connector - HP Compaq D315 Technical Reference Manual

Chapter 5 Input/Output Interfaces
5.4

SERIAL INTERFACE

All models include at least one RS-232-C type serial interface to transmit and receive
asynchronous serial data with external devices. The serial interface function is provided by the
LPC47B367 I/O controller component that includes two NS16C550-compatible UARTs.
The UART supports the standard baud rates up through 115200, and also special high speed rates
of 239400 and 460800 baud. The baud rate of the UART is typically set to match the capability of
the connected device. While most baud rates may be set at runtime, baud rates 230400 and
460800 must be set during the configuration phase.

5.4.1 SERIAL CONNECTOR

The serial interface uses a DB-9 connector as shown in the following figure with the pinout listed
in Table 5-5.
Figure 5-3. Serial Interface Connector (Male DB-9 as viewed from rear of chassis)
Table 5–7. DB-9 Serial Connector Pinout
Pin Signal
1 CD
2 RX Data
3 TX Data
4 DTR
5 GND
The standard RS-232-C limitation of 50 feet (or less) of cable between the DTE (computer) and
DCE (modem) should be followed to minimize transmission errors. Higher baud rates may require
shorter cables.
5-8 Compaq D315 and hp d325 Personal Computers
Featuring the AMD Athlon XP Processor
Table 5-7.
DB-9 Serial Connector Pinout
Description Pin
Carrier Detect 6
Receive Data 7
Transmit Data 8
Data Terminal Ready 9
Ground --
Second Edition – April 2003
Signal Description
DSR Data Set Ready
RTS Request To Send
CTS Clear To Send
RI Ring Indicator
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