Hi Brijesh,
it would be helpful to know specifically how your application looks like, so that my suggestion would be more precise. As a general rule, in RS-422 if the termination is used, it has to be placed at the end of the cable near the receiver. The value of the resistor should be able to match the characteristic impedance of the cable used, typically 100ohms or 120ohms.
Depending on your application, if the data rate is lower than 200Kbps or the cable length is short (few meters), you could even avoid terminating the line.
For a better understanding and more specific insight on this topic I recommend reading the following Application report:
Let me know if you have any other questions.
Best Regards,
Adrian
Hi Brijesh,
I am not sure I totally understand your application. If you are using the transceiver on a PCB, the same principle of using a cable applies. As for standard, the PCB trace should be laid out in order to match a similar characteristic impedance of usually around 100ohms. The termination resistor at the RS422 receiver side should always match that value in order to eliminate reflections. So, yes you have to always match the impedance.
If you're interested into this topic, I would recommend you to have a look at the following application note which gives an overall overview about
RS422 and RS485 communication:
Let me know if this helps.
Best regards,
Adrian
