Grass Valley iRouter v.6.01 - Manual (Page 61)

iControl Router
User Guide
57
UCM Control In Cable
The UCM Control In port is shared for both RS-232 and RS-422/485 interfaces. A NULL MODEM
or crossover cable is not required on this port and, in fact, the system will not work using a null
modem adapter or null modem cable. Use only a straight through one-to-one cable.
UCM Control In Serial Communication Settings
The serial port parameters are the same regardless of whether RS-232, RS-422, or RS-485 is
being used. The parameters are fixed at 9600 baud, 8 data bits, no parity, and 1 stop bit (8N1).
UCM Control In RS-232 Description
RS-232 was designed for communication of local devices It supports one transmitter and one
receiver. This standard uses single ended signals over unbalanced, unterminated wires. Single
ended means the signal is sent over one wire with respect to a single ground source.
Unterminated means the signal lines do not have impedance matching at the line ends. This
interface is useful for point-to-point communication at slow speeds and over short lengths of
cable. Most PCs come equipped with one or more RS-232 serial ports.
RS-232 Advantages / Disadvantages
RS-232 is easy to implement and has been standardized and accepted for years. Due to the
nature of RS-232, the signals are susceptible to noise and grounding problems. These
problems set a limit to cable lengths. Quintech recommends that when using RS-232, the
cable length be limited to 20 meters or approximately 60 feet. RS-232 employs point-topoint
communications, so only two devices will typically communicate with each other over the
RS-232 standard.
UCM Control In RS-422 Description
In RS-422 communications, a pair of twisted wires is used to carry a signal. The data is encoded
and decoded as a differential voltage between the two lines. As a differential voltage, the
interface is, in principle, unaffected by differences in ground voltage between sender and
receiver.
RS-422 Advantages / Disadvantages
RS-422 differential signals over twisted pair wires are less affected by noise. They therefore can
communicate at faster rates and over longer distances. RS-422 connectors are not
standardized like RS-232. Although better than the RS-232, RS-422 is still limited to one master
and up to ten receivers on the bus. Recommended maximum length is 4000 feet. The
Quintech RS-422 standard is limited to 10 receivers.
UCM Control In RS-485 Description
The UCM can be configured to communicate in RS-485 standard.