Path: utzoo!utgpu!watmath!uunet!cbmvax!ditto
From: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Newsgroups: unix-pc.general
Subject: Re: difference between ph1 and tty000
Summary: because of design flaw, ph[01] can't be opened O_RDONLY; fix available
Keywords: unixpc ph driver bogosity
Message-ID: <5736@cbmvax.UUCP>
Date: 19 Jan 89 16:33:18 GMT
References: <8974@mhuxu.UUCP>
Reply-To: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Organization: Commodore Technology, West Chester, PA
Lines: 22

In article <8974@mhuxu.UUCP> rs@mhuxu.UUCP (Bob Sanderman) writes:

[    (stty 1200; cat > /tmp/data) < /dev/ph1    ]

> the cat immediately returns
>without waiting for any data or even the modem to answer a call.

This is because of a fundamental design flaw in the Unix PC's phone driver.
The device can only be opened for data transfer using the WRONLY or RDWR
modes; opening it for input results in the driver being in "voice" mode
which is really meant only for the phone manager's use.

I recently posted a driver "patch" (called "phfx") that will completely
eliminate voice mode from the driver.  This will let your example command
work, but at the expense of eliminating the phone manager.
-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford@kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!elgar!ford
  2nd Edition, June, 1972.		ditto@cbmvax.commodore.com