ZEAP OUTPUT TO PRINTER/‘TELETYPE’
by R. Beal
Mr. J. Addey has written to the INMC saying:–
“We bought ZEAP some time ago hoping to use it on our NASCOM 1 which is
exclusively used in conjunction with an ASR ‘teletype’. End of story.
No-one from NASCOM can offer any advice as to how ZEAP may be used
except by using the original keyboard + VDU O/P.”
Here are the answers for both ZEAP 1 and ZEAP 2.
The address of the output routine is located at 0F22-0F23, so cold
start ZEAP, then return to the monitor, then alter this address to your
own routine and then warm start ZEAP. When you use ZEAP, only output
from the U command (=list to UART) and assembler output with option 04
on (TTY option) will be output to the TTY. This is extremely useful as
updates to text are carried out using the Nascom keyboard and VDU,
command 04 is entered and then the A command, for hard copy listing.
If you are simply using a serial ASCII printer, there is no need to
change the address at 0F22-0F23 because the default is to send the data
to the UART in any case. Read pages 43 and 49 of the ZEAP 1 manual
where it is explained very clearly. If you are using a parallel printer
(or serial device) which require special print handling routines, then
this pointer must be changed to direct data to the output handling
The comments above for ZEAP 1 apply also to ZEAP 2, except that the
address of the output routine is at 0F05-0F06. See appendix E, and
appendix G, as well as the description of the U command, all clearly
set out in the ZEAP 2 manual.
You may wish to use an external keyboard for input. ZEAP does nothing
special when it gets an input character, so you can activate a teletype
keyboard as described in the Nas-Sys manual under the X command. (Enter
X0.) This also works with the T4 monitor, and applies to ZEAP 1 and
ZEAP 2. If you are still back in the dark ages with T2 then bad luck,
you can’t do it without writing a special program. Using the X command
will not in this case affect output, as ZEAP itself takes control of
where the output is to go to.