Cable Data Rate
Maximum Possible Signalling Rate
The maximum permissible data rate is given below as cable length in meters. Note that the data rate is provided as signalling rate in bits per second bps. The numbers represented by the graphs are for general usage, using a generic cable. An actual maximum data rate would depend on the physical cable, the dielectric used with the cable and the capacitance of the cable.
Cable Length vs Data Rate
Note that a bit rate of up to 100k may be used up to a distance of 1200 meters. However above 1200 meters the possible data rate reduces rapidly.
Cable Length vs Data Rate vs Rise Time
Section topic; cable assemblies next page.
General rules and Cable Derating Guide Lines [for heat not speed].
The unbalanced voltage digital interface
circuit can generally be utilized on data, timing or clock, and
control circuits where the signaling rate on these circuits is up to 100
kilobits per second (kb/s). An example of an unbalanced [single ended] interface would be the RS423 Circuit [RS423 interface standard].
Most of the interface standards that use copper wire to transmit data also use a signal pair, or balanced signal.
The balanced voltage digital interface circuit can generally be utilized on data, timing or clock, and control
circuits where the signaling rate on these circuits is up to 10 megabits per
second (Mb/s). The terminated voltage digital interface circuit
can generally be utilized on data, timing or clock, and control circuits
where the signaling rate on these circuits exceeds 10 Mb/s. An example of an balanced [differential ended] interface would be the RS422 Circuit.
While the balanced voltage digital interface circuit is intended for use at higher
signaling rates [and noisier environments] than the unbalanced voltage digital interface circuit, the
general use of the balanced voltage digital interface circuit is recommended where any of the following conditions prevail:
a. The interconnecting cable is too long for effective unbalanced operation [balanced signalling operate better than unbalanced].
b. The interconnecting cable is exposed to extraneous noise
sources that may cause an unwanted voltage in excess of plus or
minus one volt measured differentially between the signal conductor
and circuit common ground at the load end of the cable [measured with a 50-ohm resistor substituted for the generator].
c. It is necessary to minimize interference with other signals. Balanced signalling uses a differential pair of signals. So any noise induced on the line would have to be coupled to both wires and in opposite polarity before it caused any interference.
