[comp.sys.ibm.pc.misc] DSZ upload problem at 19200 baud - flow control?

Gumley_LE@cc.curtin.edu.au (Liam Gumley) (02/28/91)

I am using DSZ.COM on a 386-AT to upload and download files from a VAX/VMS
system that has RZ and SZ.  The transfers are done over a direct serial link
(i.e. no modem, just cable.)

Previously I have been able to do both uploads and downloads at 9600 baud with
no problems.  A recent line upgrade now allows me to run my PC (as a terminal)
with Kermit at 19200 baud.

The problem is that while SZ(VAX) -> DSZ(PC) still works fine at 19200 baud,
DSZ(PC) -> RZ(VAX) now gets all kinds of errors at 19200 baud.
I have set the speed correctly for DSZ in each case.

The errors start with the first 1024 bytes of data transmitted, and DSZ says
Got ZRPOS.

Okay, I looked in DSZ.DOC, and ZCOMMDOC for a solution.  They indicated that
it was probably a flow control problem.  So I tried DSZ receive with
handshake on, off, slow, both, and none of them worked - I still got the
same errors.  Now it must be that the VAX cannot respond quickly enough to
the PC at 19200 baud.  I have tried a couple of different versions of the
software on both the VAX and the PC and get the same errors every time.

Can anyone offer some advice? (apart from going back to 9600 baud....)

Cheers,
Liam.

-- 
tgumleyle@cc.curtin.edu.au
#Liam E. Gumley, Department of Applied Physics, Curtin University of Technology#
#Perth, Western Australia.   >>>All opinions expressed are exclusively mine.<<<#

caf@omen.UUCP (Chuck Forsberg WA7KGX) (03/02/91)

In article <7264.27cd2589@cc.curtin.edu.au> Gumley_LE@cc.curtin.edu.au (Liam Gumley) writes:
-I am using DSZ.COM on a 386-AT to upload and download files from a VAX/VMS
-system that has RZ and SZ.  The transfers are done over a direct serial link
-(i.e. no modem, just cable.)
-
-Previously I have been able to do both uploads and downloads at 9600 baud with
-no problems.  A recent line upgrade now allows me to run my PC (as a terminal)
-with Kermit at 19200 baud.
-
-The problem is that while SZ(VAX) -> DSZ(PC) still works fine at 19200 baud,
-DSZ(PC) -> RZ(VAX) now gets all kinds of errors at 19200 baud.
-I have set the speed correctly for DSZ in each case.
-
-The errors start with the first 1024 bytes of data transmitted, and DSZ says
-Got ZRPOS.
-
-Okay, I looked in DSZ.DOC, and ZCOMMDOC for a solution.  They indicated that
-it was probably a flow control problem.  So I tried DSZ receive with
-handshake on, off, slow, both, and none of them worked - I still got the
-same errors.  Now it must be that the VAX cannot respond quickly enough to
-the PC at 19200 baud.  I have tried a couple of different versions of the
-software on both the VAX and the PC and get the same errors every time.

When sending to the VAX, you might try "handshake sw" to
enforce software flow control.  An alternative is to set a
ZMODEM packet length with "z pl1024" (normally, ZMODEM packet
length is the file length).

You might also check that ALTYPEAHEAD is enabled on the particular port
you are using.  The current VMS RZ (4.07) issues a warning if ALTYPEAHEAD
is not enabled.

System OMENVAX is a 730 with DZ11.  The 730 is not the fastest VAX ever
built, but it does compile rz/sz and Professional-YAM.  The 730 accepts
uploads at 19200 bps with few errors, but I use 9600 on it because 9600 is
just as fast.

Chuck Forsberg WA7KGX          ...!tektronix!reed!omen!caf 
Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ
  Omen Technology Inc    "The High Reliability Software"
17505-V NW Sauvie IS RD   Portland OR 97231   503-621-3406
TeleGodzilla:621-3746 FAX:621-3735 CIS:70007,2304 Genie:CAF
-- 
"Compared to tanks, journalists are cheap - and you get more for your money."
		- Saddam Hussein

jrd@cc.usu.edu (03/03/91)

In article <7264.27cd2589@cc.curtin.edu.au>, Gumley_LE@cc.curtin.edu.au (Liam Gumley) writes:
> I am using DSZ.COM on a 386-AT to upload and download files from a VAX/VMS
> system that has RZ and SZ.  The transfers are done over a direct serial link
> (i.e. no modem, just cable.)
> 
> Previously I have been able to do both uploads and downloads at 9600 baud with
> no problems.  A recent line upgrade now allows me to run my PC (as a terminal)
> with Kermit at 19200 baud.
> 
> The problem is that while SZ(VAX) -> DSZ(PC) still works fine at 19200 baud,
> DSZ(PC) -> RZ(VAX) now gets all kinds of errors at 19200 baud.
> I have set the speed correctly for DSZ in each case.
> 
> The errors start with the first 1024 bytes of data transmitted, and DSZ says
> Got ZRPOS.
> 
> Okay, I looked in DSZ.DOC, and ZCOMMDOC for a solution.  They indicated that
> it was probably a flow control problem.  So I tried DSZ receive with
> handshake on, off, slow, both, and none of them worked - I still got the
> same errors.  Now it must be that the VAX cannot respond quickly enough to
> the PC at 19200 baud.  I have tried a couple of different versions of the
> software on both the VAX and the PC and get the same errors every time.
> 
> Can anyone offer some advice? (apart from going back to 9600 baud....)
> 
> Cheers,
> Liam.

	The problem may likely be the serial board in the VAX. That is, some
have a (too) wide tolerance on the speed at 19,200 b/s and the receiving end
can be on the other side of the tolerance. In addition, cable length plays
a major role as the speed increases; I'd stay closer than 250 feet at 19,200.
On top of that the UART in the PC enters the picture if it is an 8250B (the
slow slow version). To diagnose the problem further use MS-DOS Kermit on the
PC and either LOG PACKET or SET DEBUG ON, or both, to see what arrives and
departs. Then I'd vary the packet length going to the VAX to sense interrupt
latency effects on the VAX.
	Joe D. 
> -- 
> tgumleyle@cc.curtin.edu.au
> #Liam E. Gumley, Department of Applied Physics, Curtin University of Technology#
> #Perth, Western Australia.   >>>All opinions expressed are exclusively mine.<<<#