| |
| | The RS232 Standard |
 | | For synchronous communications, the null modem cable includes an additional conductor for timing signals, and joins pins 15, 17, and 24 on one side to pins 15 and 17 on the other. |
 | | This simplified null modem cable uses only Request-to-Send (pin 4) and Clear-to-Send (pin 5) as handshaking lines; DTE Ready, DCE Ready, and Carrier Detect are not employed, so this cable should not be used with modems. |
 | | The modem generates this clock signal to control exactly the rate at which data is sent on Transmitted Data (pin 2) from the DTE device to the DCE device. |
| www.camiresearch.com /Data_Com_Basics/RS232_standard.html (5380 words) |
|