I tried the tester as below (cut & paste except the range) but just a a list of ascii garbage. I am monitoring using the microcode studeo serial communicator and have tried receiving at various speeds.
The output is via a 1K resistor.

Regards

Chris

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@ device hs_OSC, wdt_on, pwrt_on, protect_off
define osc 20

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 64 ' 2400 Baud @ 4MHz, 0.17%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

Pause 500

Start:
FOR SPBRG=15 to 100
HSEROUT ["SPBRG=",#SPBRG]
PAUSE 50
NEXT
stop 'put this in to do it only once
GOTO Start