Installation manual
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Installation Manual
Appendix B - Hardware Specifications
Cyclades-TS
verify if you think you have the correct cable and things still do not work. The most common configuration is 8N1
(8 bits of data per character, no parity bit included with the data, 1 stop-bit to indicate the end of a character).
The baud rate in a RS-232 line translates directly into the data speed in bits per second (bps). Usual transmission
speeds range between 9600 bps and 1920bps (used in most automation and console applications) to 115,200
bps (used by the fastest modems).
Cable Length
The original RS-232 specifications were defined to work at a maximum speed of 19,200 bps over distances up
to 15 meters (or about 50 feet). That was 30 years ago. Today, RS-232 interfaces can drive signals faster and
through longer cables.
As a general rule, consider:
• If the speed is lower than 38.4 kbps, you are safe with any cable up to 30 meters (100 feet)
• If the speed is 38.4 bps or higher, cables should be shorter than 10 meters (30ft)
• If your application is outside the above limits (high speed, long distances), you will need better quality (low-
impedance, low-capacitance) cables.
Successful RS-232 data transmission depends on many variables that are specific to each environment. The
general rules above are empirical and have a lot of safety margins built-in.
Connectors
The connector traditionally used with RS-232 is the 25-pin D-shaped connector (DB-25). Most analog modems
and most older computers and serial equipment use this connector. The RS-232 interface on DB-25 connector
always uses the same standard pin assignment.
The 9-pin D-shaped connector (DB-9) saves some space and is also used for RS-232. Most new PC COM
ports and serial equipment (specially when compact size is important) uses this connector. RS-232 interfaces
on DB-9 connectors always use the same standard pin assignment.
The telephone-type modular RJ-45 plug and jack are very compact, inexpensive and compatible with the phone
and Ethernet wiring systems present in most buildings and data centers. Most networking equipment and new