EIA Levels

Each serial port supports both RS-232 and RS-423 protocols. RS-232 signaling levels are between -3 VDC and -15 VDC and +3 VDC and +15 VDC. A binary 1 (0012) is anything greater than +3 VDC and a binary 0 (0002) is anything less than -3 VDC. The signal is undefined in the transition area between -3 VDC and +3 VDC. The line driver switches at -10 VDC and +10 VDC with a maximum of -12 VDC and +12 VDC in RS-232 mode. RS-423 is similar except that signaling levels are between -4 VDC to -6 VDC and +4 VDC and +6 VDC. The line driver switches at -5.3 VDC and +5.3 VDC with a maximum of -6 V and +6 VDC. Switching from RS-232 to RS-423 protocol is accomplished by changing jumpers J2604 and J2605. Jumper positions 1 and 2 are for RS-232 and jumper positions 2 and 3 are for RS-423.

The preferred signaling protocol is RS-423. The higher voltages of R-232 make it difficult to switch at the higher baud rates. The maximum rate for RS-232 is approximately 64 Kbaud while the maximum rate for RS-423 is 460.8 Kbaud. The system default is set to RS-232.