"pon" gives "ttyS overrun" after upgrade

[Problem now solved: is brltty Debian package.
Specifically, /etc/rcS.d/S25brltty and /sbin/brltty.
If you don't need this package then remove this package.
If you need this package, well, you've got some debugging to do.
Or, alternatively, come up with a different way
to set up your internet connection]

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I did an "apt-get upgrade" and, now, when I execute "pon", my modem
won't connect. The modem seems to be making the same connection
sounds as before the upgrade; also, the modem is working in Window98.

I have syslog records from before/after the upgrade. After upgrade,
I notice this message:

kernel: ttyS: 1 input overrun(s)

In the remainder of this posting, I provide the following information:

- miscellaneous command-line
- /etc/ppp/peers/provider
- successful syslog before the upgrade
- unsuccessful syslog after the upgrade

Any help would be greatly appreciated. I've run dry on ideas and am
on the verge of doing a reinstall of Debian.

=============================================
=============================================
=============================================

==== start of miscellaneous command-line ====

$ setserial -bg /dev/ttyS*
/dev/ttyS0 at 0x03f8 (irq = 4) is a 16550A
/dev/ttyS1 at 0x02f8 (irq = 3) is a 16550A
/dev/ttyS2 at 0x03e8 (irq = 4) is a 16550A

$ setserial -aq /dev/ttyS2
/dev/ttyS2, Line 2, UART: 16550A, Port: 0x03e8, IRQ: 4
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

==== end of miscellaneous command-line ====

==== start of /etc/ppp/peers/provider ====

# This optionfile was generated by pppconfig 2.3.2.
#
#
hide-password
noauth
connect "/usr/sbin/chat -v -f /etc/chatscripts/provider"
debug
/dev/ttyS2
115200
defaultroute
noipdefault
user "###MY_USER_ID###"
remotename provider
ipparam provider
usepeerdns

==== end of /etc/ppp/peers/provider ====

==== start of successful syslog before the upgrade ====

Jun 30 08:59:23 box pppd[10108]: pppd 2.4.1 started by knoppix, uid 1000
Jun 30 08:59:24 box chat[10112]: abort on (BUSY)
Jun 30 08:59:24 box chat[10112]: abort on (NO CARRIER)
Jun 30 08:59:24 box chat[10112]: abort on (VOICE)
Jun 30 08:59:24 box chat[10112]: abort on (NO DIALTONE)
Jun 30 08:59:24 box chat[10112]: abort on (NO DIAL TONE)
Jun 30 08:59:24 box chat[10112]: abort on (NO ANSWER)
Jun 30 08:59:24 box chat[10112]: abort on (DELAYED)
Jun 30 08:59:24 box chat[10112]: send (ATZ^M)
Jun 30 08:59:25 box chat[10112]: expect (OK)
Jun 30 08:59:25 box chat[10112]: Zz^PCARRIER^M
Jun 30 08:59:25 box chat[10112]: ATZ^M^M
Jun 30 08:59:25 box chat[10112]: OK
Jun 30 08:59:25 box chat[10112]: -- got it
Jun 30 08:59:25 box chat[10112]: send (ATDP###My_ISP_Number####^M)
Jun 30 08:59:25 box chat[10112]: expect (CONNECT)
Jun 30 08:59:25 box chat[10112]: ^M
---no "kernel: ttyS: 1 input overrun(s)" occurs
Jun 30 08:59:50 box chat[10112]: ATDP###My_ISP_Number####^M^M
Jun 30 08:59:50 box chat[10112]: CONNECT
Jun 30 08:59:50 box chat[10112]: -- got it
Jun 30 08:59:50 box chat[10112]: send (\d)
Jun 30 08:59:51 box pppd[10108]: Serial connection established.
Jun 30 08:59:51 box pppd[10108]: Using interface ppp0
Jun 30 08:59:51 box pppd[10108]: Connect: ppp0 <--> /dev/ttyS2
----key delta point
Jun 30 08:59:53 box pppd[10108]: local IP address 209.226.185.176
Jun 30 08:59:53 box pppd[10108]: remote IP address 209.226.185.241
Jun 30 08:59:53 box pppd[10108]: primary DNS address 199.166.210.2
Jun 30 08:59:53 box pppd[10108]: secondary DNS address 199.166.210.5
...
Jun 30 14:57:19 box pppd[10108]: Terminating on signal 15.
Jun 30 14:57:19 box last message repeated 2 times
Jun 30 14:57:19 box pppd[10108]: Connection terminated.
Jun 30 14:57:19 box pppd[10108]: Connect time 357.5 minutes.
Jun 30 14:57:19 box pppd[10108]: Sent 1710469 bytes, received 52530926 bytes.
Jun 30 14:57:19 box pppd[10108]: Terminating on signal 15.
Jun 30 14:57:19 box pppd[10108]: Exit.

==== end of successful syslog before the upgrade ====

==== start of unsuccessful syslog after the upgrade ====

Jul 3 20:28:38 box kernel: CSLIP: code copyright 1989 Regents of the University of California
Jul 3 20:28:38 box kernel: PPP generic driver version 2.4.2
Jul 3 20:28:38 box pppd[1177]: pppd 2.4.2 started by knoppix, uid 1000
Jul 3 20:28:39 box chat[1179]: abort on (BUSY)
Jul 3 20:28:39 box chat[1179]: abort on (NO CARRIER)
Jul 3 20:28:39 box chat[1179]: abort on (VOICE)
Jul 3 20:28:39 box chat[1179]: abort on (NO DIALTONE)
Jul 3 20:28:39 box chat[1179]: abort on (NO DIAL TONE)
Jul 3 20:28:39 box chat[1179]: abort on (NO ANSWER)
Jul 3 20:28:39 box chat[1179]: abort on (DELAYED)
Jul 3 20:28:39 box chat[1179]: send (ATZ^M)
Jul 3 20:28:39 box chat[1179]: expect (OK)
Jul 3 20:28:43 box chat[1179]: ATZ^M^M
Jul 3 20:28:43 box chat[1179]: OK
Jul 3 20:28:43 box chat[1179]: -- got it
Jul 3 20:28:43 box chat[1179]: send (ATDP###My_ISP_Number####^M)
Jul 3 20:28:43 box chat[1179]: expect (CONNECT)
Jul 3 20:28:43 box chat[1179]: ^M
---BAD!!!
Jul 3 20:29:12 box kernel: ttyS: 1 input overrun(s)
Jul 3 20:29:12 box chat[1179]: ATDP###My_ISP_Number####^M
Jul 3 20:29:12 box chat[1179]: CONNECT
Jul 3 20:29:12 box chat[1179]: -- got it
Jul 3 20:29:12 box chat[1179]: send (\d)
Jul 3 20:29:13 box pppd[1177]: Serial connection established.
Jul 3 20:29:14 box pppd[1177]: Using interface ppp0
Jul 3 20:29:14 box pppd[1177]: Connect: ppp0 <--> /dev/ttyS2
---key delta point
Jul 3 20:29:39 box pppd[1177]: Hangup (SIGHUP)
Jul 3 20:29:39 box pppd[1177]: Modem hangup
Jul 3 20:29:39 box pppd[1177]: Connection terminated.
Jul 3 20:29:40 box pppd[1177]: Exit.

==== end of unsuccessful syslog after the upgrade ====