Fasial,
thankyou for your reply. Its great to find people who are working on the some what same project as i like to work...you people cannot imagine that it took me 1 year to find such discussion forum where i find helpful guys like you..
I will mail you fasial but i think for the saek for this discussion forum we should keep posting things on this forum so that it can benefit others also..
So may i know what type of PBX you are designing like number of truncks and extensions...

And one question which iam asking every one is:-

1) Is programming for a only 8 Lines Intercom using the same SLIC , MT8816 is comparativly easy than for a PBX ?

2) What are the steps that are included in writing the codes for such a 8 Lines Intercom system...? Like i have seen a tutorial on this website for real time clock and in that they indicated that we need TICKS, MINUTES, SECONDs variables then we have to write ISR for one of them etc..
So whats the flow chart for simple SLIC based intercom system.