RS232 to RS485 Conv issue

[assadmahmood]

Greetings EveryBody!

I AM USING:
I am using B&B Electronics RS232 to RS485 converter (Model 485COSR, datasheet attached), for conversion it has MAX491 type full duplex IC in it and I connected this conerter with Computer via RS232 and on the other hand in my circuits LTC485 is used.


WHAT I DID IS:
Here I had to transform 4wire to 2 wire, I googled for it and I found that it can be done by shorting its TDA- and RDA- with each other & TDB+ and RDB+ with each other I did the same and and transformed 4wire into 2 wire for LTC485 (on the other end).

ISSUE:
If circuit transmits any data to PC (LTC485 to converter)then it received successfully but when PC transmits any data (converter to LTC485) then it is echoed back to PC chracter by character but not received successfully on the other end (LTC485 end).

Kindly suggest me at where I am going wrong.View attachment 232(25) to 485(25).pdf

 

[GUMY]

4 wire comunication is called RS422 and it is full-duplex, 2 wire is called RS485 and it is half duplex. This two systems can be mixed as You did it, but protocols must be suitable for that. Therefore, it is normal that signal is echoed back to PC as TX and RX are wired together. Probable cause for not receiving anything on side of Your device is, that You do not put LTC485 to receive mode?

 

[assadmahmood]

Sir LTC485 is there on the microcontroller end, I guess it is might getting receive the data but not the actual one, may be corrupted or with garbage, does this happens?