Chapter 4 Rs232 Pinouts And Port Cabling; Introduction; The Rs232 Standard - Brainboxes CC-357 User Manual

PCI VelocityRS232/422/485 RS232 Pinouts & Cabling
Chapter 4
RS232 PINOUTS AND PORT
CABLING.

Introduction.

This chapter gives details of the 9 and 25 pin RS232 pin outs,
cabling and connections, with information on how to connect the
serial ports of two PCs and how to make a selftest loop back
connector.

The RS232 Standard.

The RS232 standard is ancient in computer industry terms.
Introduced in 1962, it is now widely established. RS232 is a slow
speed, short distance, single ended transmission system (i.e. only
one wire per signal). Typical RS232 maximum cable length is 50
feet with a maximum data rate of 20K bits per second.
Figure 4-1. RS232 Point To Point Connection.
TTL D R TTL
Ground Ground
RS232C Standard
1 Driver 1 Receiver
Line Length Max Data Rate
50 Feet = 15m 20 Kbits/sec
Chapter 4 Page 64