[comp.sys.ibm.pc] question about the response of HP plotter

wei@tiger.UUCP (05/29/87)

I tried to send a string 'IN;SP 1;PA 500,1000;' to a HP plotter (7470)
using assembly language and using BIOS call 14H with ah=1.
The string is a HP-GL command asking the plotter to be initialized and
select pen 1 and then goto position 500,1000.
The plotter has no reponse at all if I send the string characters one
by one succesively.
However, it reponds correctly if I put a delay loop ( for about 1ms )
after each character.
Is this situation normal? The HP plotter needs some time to put the
coming character into its buffer before it can receive the next one !
Or I am doing something wrong ?!
HP Wei     wei@princeton.UUCP