The Link 4+0-Internal Intercom-Help me out!

[lanre]

Concerning the schematic of the above project which I intend doing, am still havng some problems:
Is there any alternative to the audio transformer (impedance-matching xformer)used in the project? And is ther any common equipmnt where I can see a sample to remove it from the scrap? Is that specification (1k/8R centre tappd at 1K) compulsory or any type will work? Am really having problem getting it here in Nigeria.

Is the specification IC2  wth no MC45436 correct because I was only able to get MC4543? Must CD 4013 be a dual RS flip-flop or can it be D-flip-flop? Will CD4515B but 4 to 16 decoder also go for the IC3 in place of 1 to 16?


Can I also connect  more than 4 phones to the free legs of the IC3?

[MP]

I downloaded the word version of this project to see if I could hep you, but it does not have a Bill of Materials.

Most of the questions you have can be found by using the data sheets for the parts. The 1K to 8 ohm transformer is very common for anything connected to a phone line. Perhaps you can find some old phone equipment.
Regarding the ICs, I would recommend that you stay with the items recommmended in the project. If you must use a different IC, look at the differences in the data sheets for both devices.
Hope that helps you somewhat.

MP

[lanre]

Pls, the ICs (MC45436 DTMF decoder, CD 4515B 1x16 decoder and CD4013B RS flip flop) required for the above project are just too scarce. I searched the web and even for the datasheets and possible replacement all to no avail. The replacemnts gotten from the market didn't satisfy me with their descriptions.
I got CD4543BE (Cmos BCD-to-& segment  latch decoder for LCD) in place of MC45436-which I was informed has a wrong specification, CD4515BE(cmos 4-bit latch/4-to-16 line decoder with output low on select) in place of CD4515B.

Pls help me out in any form as am really feeling sad about the current development. My project is at stake.
Lanre :(