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RS232 Physical Properties

USB DriverYou can find the RS232 pinout on this website as well. These are the other characteristics of the RS232 interface which you might also find of interest. Below we will explain the communication methods capable of communicating in different environments. Note that voltage and distance is important with the RS232 standard. Also note the baud rates with distance as well as other specifications so look at the FT232R driver also on this website.

RS232 Physical Properties

Voltages differ and these do affect communication over the cables. As an example an RS232 with a -9.3 V, compared to -11.5 V has difficulty communicating with an industrial computer in a high noise environment. You will also note that there will be a difference in error levels over the two voltages. Cable length is also important and this does affect the communications as an example the maximum length is 50 feet, or the cable length equal to a capacitance of 2500 pF. That is very important as a  low capacitance cable will allow you to span longer distances and still be within the standard compared to a high capacitance cable. You should check the cable before you buy it. You will note the difference below as example cables.

P/N Construction OD Mutual Capacitance
2210 4 pair 24 AWG no shield Category 6 .220” 13.5 pf/ft
8508 4 pair 24 AWG O/A shield (RS232) .277” 13 pf/ft
9508 4 pair 28 AWG O/A shield (RS422) .233” 15.5 pf/ft
9720 2 pair 22 AWG pairs shielded DS-1 oval 15.0 pf/ft

 

Part Number : 2210 (Quabbin Cable)

Electrical Characteristics : (For 100m of Cable)
Capacitance, Mutual: 13.5 PF/FT. AT 1 MHz
Dielectric Withstanding, Min:  1500V RMS
Voltage Rating, Max: 300V

 

Part Number : 8508 (Quabbin Cable)

Electrical Characteristics : (For 100m of Cable)
Capacitance, Mutual: 13.0 PF/FT. AT 1 MHz
Capacitance, Mutual: 24.0 PF/FT. AT 1 MHz
Dielectric Withstanding, Min:  1500V RMS
Voltage Rating, Max: 300V

 

Part Number : 9508 (Quabbin Cable)

Electrical Characteristics : (For 100m of Cable)
Capacitance, Mutual: 15.5 PF/FT. AT 1 MHz
Capacitance, Mutual: 27.5 PF/FT. AT 1 MHz
Dielectric Withstanding, Min:  1500V RMS
Voltage Rating, Max: 300V

 

Part Number : 9720 (Quabbin Cable)

Electrical Characteristics : (For 100m of Cable)
Capacitance, Mutual: 15.0 PF/FT. AT 1 MHz
Dielectric Withstanding, Min:  1500V RMS
Voltage Rating, Max: 300V

 

Baud Rates with distance

There have been a number of options with regards to the baud rate an distance. The lower the baud rate usually the longer the cable can be. The example below was made by Texas Instruments in this regards. If speed is reduced as can be seen below by say a factor 2 or 4 then the maximum length increases as cab be seen from the table listed below. .

RS232 cable length according to Texas Instruments
Baud rate Maximum cable length (ft)
19200 50
9600 500
4800 1000
2400 3000

 

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About Tracey Brown

I develop websites and content for websites related to high tech from around the world. See more pages and content about technology such as USB and other IT developments around the world. You can follow the other websites as well and search this website for more information on mobile phones and other USB components.