hello all,
Iam studying a PCB of 16 Lines Intercom system based on At89c52, Mt8816 and supports pulse dailing telephone Sets. In this circuit the designer has used 4 small PCBS , each representing 4 lines using four 5 volts relays , four C945 transistors, four A673 transistors and one Quad Comparator LM3900N. This small pcb type card acts like SLIC for 4 Lines. Now for 16 Lines there are 4 such cards. My question is the designer has used :-

Two HCF4094B ( 8-Stage SHift & Store Bus register with 3-state outputs)
and Two 74HC165N ( 8-bit parallel-in / serial out shift register )...

for 16 Users.

Now have seen the datasheets but iam looking for some application notes to use the above devices with 89c52 controller....is there any please guide me....

or should i place the connections of the above mentioned IC with MT8816 pins and controller pins so that some one can explain why these pins are connected in such a way...