Content-Type: text/plain; charset=koi8-r
X-MIME-Autoconverted: from 8bit to quoted-printable by ns1.ptt.yu id VAA19919

I have two schematics:
one is with XR2211 and XR2206 - never work
XR2211, 4046, 4049 - work but a lot of problems

Lea wrote:

> > No, i need simple 1200 AFSK modem with PIC microcontroller...
> > I got some school assignemt, and i must build it...but also i need it..
> > I like to work on packet and it will be nice to have modem with PIC...
> > Can anybody help me with schematic???
> > THANKS!
> >
> Hi!, I am currently working on something like that, modem is no the problem
> for you, just use the MX614 (5v) or a xr2206 (TX) xr2211 (RX)(9V) as modems.

Not to talk abt finding those MX614

> š
> The difficult part is build the HDLC packet, not talking about receive,
> specially if you want to work with the full specification of the Level 2
> layer of the AX25 protocol.

Yeah..

> š
> I Was working on with it, but only uses UI level 2 and a custom layer 3
> and used about 3.5 Kb of pic space on a 16C74 programmed in ASM, custom
> serial interface (SPI like), and 8530 SCC.
>
> I will strongly recommend to use the Z8530 , It's a bit complicated to
> learn how to program it, but it is very powerful.
> A smaller (easier to program) and cheaper version is the Z80SIO that
> can be interfaced very easy with a pic mcu.
> But this one does not generate the NRZI, and you must do it by hardware,
> it requires 4 TTL IC's to do the job, I can send you a schematic of how to
> implement NRZI for the Z80SIO if you like.
>
> Another problem that you will find is the memory space, only 192 bytes on
> the 16C73/4 , I'm using another pic connected to the custom SPI Bus that
> controls a memory chip (like a software hard drive), I know that it sounds
> weird but was the only idea at that time and works good enough.
>
> hope it helps
> see you.
>
> šš Leandro J. Laporta (LU2AOQ)
> šš mail: lu2aoq@yahoo.com
> šš wrk: Arg. Assoc. for Space Technology.
> šš ham: TCP/IP high speed group HSG
>
> __________________________________________________
> Do You Yahoo!?
> Talk to your friends online with Yahoo! Messenger.
> http://im.yahoo.com

Content-Type: text/x-vcard; charset=koi8-r;
 name="mpavlica.vcf"
Content-Description: Card for Milan Pavlica (YU7AEC)
Content-Disposition: attachment;
 filename="mpavlica.vcf"
Content-Transfer-Encoding: 7bit

Attachment converted: birth:mpavlica.vcf (TEXT/CSOm) (00008428)