Problem with a xon/xoff flow control in a digi acceleratot 8 port

Hi I have a digi board with Red Hat Linux 7.2.
The problem is that when I send a job and if the printer is not ready or is off the job is send and when the printer is ready the job is over.

Also we have seen that when the job have more than nine page at the page 10 the printed information have not sense , all is garbage , it seam to be that the xon/xoff is not working properly.

this the configuration that we are using
For xon/xoff flow control add the following 2 lines in ‘/etc/rc.d/rc.local’:

–cat < /dev/ttyD000 > /dev/null & (ttyD000 is just an example)

–ditty ixon ixoff –ixany /dev/ttyD000 (ttyD000 is just an example)

Is some body may help me I will appreciate

Your flow control strings look good, minus the – on the front. Do the dashes actually appear in those strings in your rc.local file or is that a mistype?

When I tried the commands with – on the front here as you posted, I get “command not found”. What does ditty -a /dev/ttyD000 show? Are the flow control parameters in fact being set?

michael the – in front of the posted messages where capture fron a telnet in the file really dont appear.
michael a rare condition is that when I send a job and if the printer is offline or disconnectec the job is send and when I power on the printer some part of the job is lost.
may you give me some clue about this.
I will appreciate it .

thank you


Hi Ralph:

In order for the host server to recognize that the printer is off-line, you will need to use hardware flow control. Software flow control (-s and q) is not sufficient, since when the printer is off-line, it will not send a -s to tell the host server to ‘stop’.

To do this, wire the printer’s hardware flow control signal to the Digi port’s CTS signal and activate the port setting for hardware flow control:

ditty -ixon -ixon ctspace ttyD000

When the CTS signal drops, the host server will hold the print job until CTS is restored.

Hope this helps!

Hello ,
Thank you for the posted message,
I will try with it ,

I wrote a digi and a technician told me that I do the next:

For xon/xoff flow control add the following 2 lines in ‘/etc/rc.d/rc.local’:

–cat < /dev/ttyD000 > /dev/null & (ttyD000 is just an example)

ditty ixon ixoff –ixany /dev/ttyD000 (ttyD000 is just an example)

You can first run these two commands from the command line. Add them to rc.local so they are executed when you boot.

If that fails, try DTR flow control:

–Change the printer configuration from xon/xoff to DTR

–Change the ditty command given above to:

ditty ctspace /dev/tyyD000

Now this the configuration that I have in the port 5 of the digi.
forcedcd -altpin -fastbaud (2400)

rtspace -dtrpace ctspace -dsrpace -dcdpace


startc = 0x11 stopc = 0x13

-aixon astartc = 0x0 astopc = 0x0

onstr \033[5i offstr \033[4i term vt100

maxcps 100 maxchar 50 bufsize 2048

speed 2400 baud; rows 0; columns 0; line = 0;

intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ;

eol2 = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;

lnext = ^V; flush = ^O; min = 1; time = 0;

-parenb -parodd cs8 hupcl -cstopb cread clocal crtscts

-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon ixoff

-iuclc -ixany -imaxbel

opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0

isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt

echoctl echoke

If you have some other idea or clue please let me know.

The problem I see here is your ditty results show ctspace, ixon, and ixoff activated on the port. This will cause problems, since you cannot use both hardware and software flow control on a port at the same time.

Again, if you need the print job to stop when the printer is off-line, only hardware flow control will provide this functionality.