With single ended connections, they are the same as for RS-232. AFAIK there is no standard for differential connections. Only standard I know of with differential connections is V.35, but you won't be crazy about the connector.Hi team
I need to use RS485 and DB9 connector, is there a standard way to connect DB9? I have googled it already, it looks like there is not a standard of how to connect RS485 to DB9 connector??
Thanks guys!
This is one way doing it, don't think it's universally accepted standard, however.
I am hoping to find a standard/universally accepted DB9 connection (which pins for what)I have never come across a RS485 'standard' socket, but the DB9 was used to replace the 25pin DB25 socket for RS232 COM port.
Max.
I wouldn't go with this info. The "RS-485" column on the DB-9 is not even full duplex. It has just one signal pair. I have used RS-422/485 a lot over the years. There are some common pinouts but I wouldn't call them standards. Remember, standards are great. Everyone should have one.
How would you connect them, if you need to use RS485 on a DB9, with full duplex. I see some use 1,2,3,4. Some use 2,3,7,8. GND can be 4 or 5 or 6.I have used RS-422/485 a lot over the years. There are some common pinouts but I wouldn't call them standards. Remember, standards are great. Everyone should have one.
I usually had a particular piece of equipment to connect with my custom boards. I would just make my pinout compatible with the other equipment. This allowed simple cables without a lot of crossovers. For example, Digi International makes terminal servers which support multiple signal level protocols. Here is an example. Again, nothing standard that I know. There may be an accepted practice in some application areas. Or, pick something like the Digi pinout and "claim compatibility".How would you connect them, if you need to use RS485 on a DB9, with full duplex. I see some use 1,2,3,4. Some use 2,3,7,8. GND can be 4 or 5 or 6.
What would you use if you were doing it and want most compatibility?
You will need a chip with enables (DE *RE) for half-duplex operation as that's usually a standard configuration with many devices.I think I will stick a terminal block on it just like others.
What do you think of this chip? I will need to do 115Kbps, full duplex, 1000 meters max, point to point connection.
https://www.st.com/content/ccc/reso...df/jcr:content/translations/en.CD00003152.pdf
Within the TIA-485 specification, all the drivers and receivers are about the same. That is the point of having an electrical specification. There are some devices which go beyond the spec. For example, there are some very, very fast devices from T.I. which I have used to transmit 30 nanosecond pulses for over 15 meters. Your requirement is within the spec and the device you cite should be fine. I suggest picking a device with functionality and pinout shared with other devices. This gives you a second source. BTW, the "input fail safe" feature is good and fairly standard now(?). More important is the cabling, shielding, grounds and termination.I think I will stick a terminal block on it just like others.
What do you think of this chip? I will need to do 115Kbps, full duplex, 1000 meters max, point to point connection.
https://www.st.com/content/ccc/reso...df/jcr:content/translations/en.CD00003152.pdf
by Jake Hertz
by Jake Hertz
by Jerry Twomey
by Jake Hertz