How do I get *8* data bits *no* parity?

Jeff Mann mann at intacc.uucp
Fri Nov 4 06:39:03 AEST 1988


In article <130 at tree.UUCP> stever at tree.UUCP (Steve Rudek) writes:
>We're running Micrport System V/AT release 2.4 and need to change the tty
>default for incoming modem calls from the default (7 data bits even parity)
>to 8 data bits no parity to better accomodate new callers.  About 6
>months ago, under 2.2, I spent quite a bit of time experimenting with the 
>gettydefs file.  As I recall, I tried changing the standard entry:
>
>1200# B1200 HUPCL PARENB CS7 CLOCAL OPOST ONLCR # B1200 HUPCL SANE IXANY TAB3 #login: #1200
>
>to:
>
>1200# B1200 HUPCL CS8 CLOCAL OPOST ONLCR # B1200 HUPCL SANE IXANY TAB3 #login: #1200
>
>but it didn't make any significant difference.  Why not?
>
>I was told by one of the tech support folks at microport that the "#" in the
>center of the gettydefs record delimits line condition BEFORE login from
>line condition AFTER login.  Is this correct?  In general, I'd be fascinated

Yes, the first part of the line is the settings that getty uses before 
executing /bin/login.  It starts off in "raw" mode so that it can "adapt the
system to the speed and type of terminal being used."  However, Microport
says that "Data terminals using 8-bit protocols are not supported through
gettydefs (#316, ver 1.3, known limitation)".  That means that the change
you made above won't work, because the "autoconfigure" feature of getty can't
handle 8 bits.  This one had me stumped until I tried:

1200#B1200 OPOST ONLCR HUPCL# CS8 BRKINT ISTRIP ICRNL IXON IXOFF TAB3 OPOST ONLCR B1200 CREAD ISIG ICANON ECHO ECHOE ECHOK IXANY HUPCL#\nLog in as 'newuser' if you are one\nlogin: #300

That is, force CS8 to be used AFTER the login name has been received.  This
means that ANYONE logging in will be set to 8 bits, which is probably what
you want.  The login prompt is sent with no parity, because no data format 
is specified in the initial settings.

I don't claim to be a wizard or anything ( I'm sure a few people will have a
good laugh at my gettydef line ) but it works!

-- 
| Jeff Mann - Inter/Access Videotex, Toronto  ...uunet!mnetor!intacc!mann  |
| "A picture is worth 256 thousand words"  {utzoo, utgpu}!chp!intacc!mann  |



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