How does RS232 work ?

The serial interface is a two-way communications device meaning that it can send and receive data at the same time.

The speed in which the interface communicates is denoted by the ‘baud rate.’
ViewZ’s Public view monitor and LCD built in 4/8ch DVR operate at a baud rate of 9600.

The RS-232 standard imposes a cable length limit of 50 feet; however, this is usually ignored since a cable can be as long as 10000 feet at baud rates up to 192000 if you use a high quality, well shielded cable. The external environment has a large effect on lengths for unshielded cables. In electrically noisy environments, even very short cables can pick up stray signals. For Orion’s Public view monitor and LCD built in 4/8ch DVR, the following offers some reasonable guidelines for 24 gauge wire under typical conditions.

Baud Rate: 9600
Shielded Cable Length: 250
Un-shielded Cable Length: 100