Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
01/10/09 09:48
Read: times


 
Msg Score: -1
 -1 Answer is Wrong		 #161402 - Yes (Little Maths)
Responding to: ???'s previous message
Jecksons Ben said:
Here's he line...

TXD----------------TXD
RXD----------------RXD
DCD----------------DCD
CTS----------------CTS
TXDClock-----------TXDClock
RXDClock-----------RXDClock

VCC----------------VCC
GND----------------GND

THat's from Card to modem
Must be maintain 115K2.
Could I used CAT-5 and with distance 20-40 meters from card to modem at mast?

Thank's
Jeckson Ben


CAT5E (UTP) cable has a capacitance of 15pF/Feet @ Impedance of 100Ohm. For 115Kbps you require about 1200pF total line capacitance , along with your connector and driver capacitance say 150pF . your Cable length comes out to be around 20meters? no more than that .
Also there is a word of caution not to connect any suppressor device on the line .


-Ap



List of 28 messages in thread
TopicAuthorDate
Someone gave me suggest            01/01/70 00:00      
   Unhelpful subject line            01/01/70 00:00      
   I would use RS485 instead            01/01/70 00:00      
      it would be easier ..            01/01/70 00:00      
      rs-485 with fullduplex            01/01/70 00:00      
         Not 485            01/01/70 00:00      
            rs-485 not the rs-232 signal            01/01/70 00:00      
               Have you actually looked at any datasheets yet?            01/01/70 00:00      
         More details , RTS, DTR            01/01/70 00:00      
            6 lines uart and 2 power supply            01/01/70 00:00      
               RE: Could I used CAT-5            01/01/70 00:00      
               Yes (Little Maths)            01/01/70 00:00      
                  speed??            01/01/70 00:00      
                     You do the maths!            01/01/70 00:00      
                  1200pF ?            01/01/70 00:00      
                     Similiar confused me...            01/01/70 00:00      
                        One more point.            01/01/70 00:00      
                           boost the driver current            01/01/70 00:00      
                              No linear relationship            01/01/70 00:00      
                     Its EIA- 232 D&E standard            01/01/70 00:00      
                        Not relevant here - beyond the spec!            01/01/70 00:00      
                           3 TX and 3 Rx distance 20 m and 115K2            01/01/70 00:00      
                              What does the datasheet tell you?            01/01/70 00:00      
                                 Thank's            01/01/70 00:00      
                                    Try this one aswell            01/01/70 00:00      
                                    before testing            01/01/70 00:00      
                                       What "testing"            01/01/70 00:00      
   RE: The data speed must 115K2            01/01/70 00:00      

Back to Subject List