Firs i think we mus wait a Ravi signal before posting and re-posting our ideas because we don't know what he wants or needs.

Are still living with those old 12 cycle micros runing at 12MHz or something? No
If one uses a better derivate say P89V51RD2 running at 40MHz in 6 cyle mode some other derivate in single cycle mode I don't I still thinking that will be slooow (two less 'o' ;-D)in soft uart for 10 at the same time.

I never said my scheme will cater to all 10 devices simultaneously.. then put a switch (not a mechanical one just a soft controlled one)

..RS485...RS422.. I say nothing about that

I don't see any significant advantage in using Hard UART except for increased cost on hardware and size of hardware. However i can see a GREAT adventage using a hard uart with internal fifo as i say, and a little increase of size, take a look in phillips website there are very small

Whats the harm in handling one device at a time and putting others on hold using handshake as in my scheme. then use a simple switch

Anyways for PC side communication you have only one channel and you can't send simultaneously the data to or from all those 10 devices due to this PC communication channel bottleneck. Ok, i agree, then is not good aproach from the start

- You say that he implement put some protocols.. but may be he can't if the 'slaves' devices are done
The protocol has nothing do with slaves slave will just communicate normally. The protocol will be acting in between PC and the 8051 shown in my shematic. Ok but you still needing the special PC soft

- You say is 'cheapest' and i think as some one says: ...
I know the whole issue ...made in fast typing or poor english I leave it to you to decide. Then ok is 'other option' i think the same is not wrong, just other option. My english is poor too.

Who says a standard program will be usefull if RS485 is used you will need a special software even if a RS485 is used. I say nothing about RS485-422

Now ball is in your court Please Justify your Rating. Please let the ball stay in Ravi´s court because seems he is not interested an we are spenting our time

Thanks & Regards,
Prahlad Purohit
I agree: Thanks & Regards
Félix Díaz

PD: If you want tomorrow i will post you a + point ;-D