I've used the 12C509 OTP at 9600 with great success. But just
receiving data. I dont use RS-232>TTL converter, just a 27K resistor.

Octavio
======================================================
Octavio Nogueira  - e-mail:   nogueira@mandic.com.br
http://www.geocities.com/~oct_nogueira
"ProPic" Production PIC Programmer Windows under US$20
====================================================== ----
De: David Duffy <AVD@MAILBOX.UQ.EDU.AU>
Para: PICLIST@MITVMA.MIT.EDU
Data: Sexta-feira, Setembro 05, 1997 12:55
Assunto: 12C509 @ 9600

>Has anyone tried to use the 12c509 at 9600 Baud ? (4Mhz OTP's)
>It works well at 2400 Baud, but even when using the on-chip calibration
>value not all chips work at 9600. I'm guessing that the timing must be
>off enough not to lock. The 509 is being fed from a PC via a RS-232 > TTL
>converter. When I use the JW chip, all is OK. I've run the simulator with
>stopwatch and I get the exact bit delays required. I get the feeling that
>9600 Baud with these chips is never going to be reliable using the 4Mhz
>internal oscillator. Any ideas or comments would be appreciated.  :-)
>Thanks...