If the below doesn't help, please give me details on how to get the information you want. It will be at least Monday before I can check it, unless I hear from you in the next couple of hours. The strace items were so long that it would be almost impossible to get them in here, and the top portions were trundcated so I couldn't see which one was being straced in many cases. Can you let me know how to handle these to get you useful info? Thanks! roger@roger-desktop:~$ sudo uname -a [sudo] password for roger: Linux roger-desktop 3.2.0-35-generic #55-Ubuntu SMP Wed Dec 5 17:42:16 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux roger@roger-desktop:~$ roger@roger-desktop:~$ sudo dmesg|grep tty [sudo] password for roger: [ 0.000000] console [tty0] enabled [ 1.365228] 0000:04:01.0: ttyS4 at I/O 0xd000 (irq = 17) is a 16550A roger@roger-desktop:~$ sudo ls -al /dev/ttyS? crw-rw---- 1 root dialout 4, 64 Dec 28 08:20 /dev/ttyS0 crw-rw---- 1 root dialout 4, 65 Dec 28 08:20 /dev/ttyS1 crw-rw---- 1 root dialout 4, 66 Dec 28 08:20 /dev/ttyS2 crw-rw---- 1 root dialout 4, 67 Dec 28 08:20 /dev/ttyS3 crw-rw---- 1 root dialout 4, 68 Dec 28 08:20 /dev/ttyS4 crw-rw---- 1 root dialout 4, 69 Dec 28 08:20 /dev/ttyS5 crw-rw---- 1 root dialout 4, 70 Dec 28 08:20 /dev/ttyS6 crw-rw---- 1 root dialout 4, 71 Dec 28 08:20 /dev/ttyS7 crw-rw---- 1 root dialout 4, 72 Dec 28 08:20 /dev/ttyS8 crw-rw---- 1 root dialout 4, 73 Dec 28 08:20 /dev/ttyS9 roger@roger-desktop:~$ sudo cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:unknown port:000003F8 irq:4 1: uart:unknown port:000002F8 irq:3 2: uart:unknown port:000003E8 irq:4 3: uart:unknown port:000002E8 irq:3 4: uart:16550A port:0000D000 irq:17 tx:0 rx:0 CTS|DSR 5: uart:unknown port:00000000 irq:0 6: uart:unknown port:00000000 irq:0 7: uart:unknown port:00000000 irq:0 8: uart:unknown port:00000000 irq:0 9: uart:unknown port:00000000 irq:0 10: uart:unknown port:00000000 irq:0 11: uart:unknown port:00000000 irq:0 12: uart:unknown port:00000000 irq:0 13: uart:unknown port:00000000 irq:0 14: uart:unknown port:00000000 irq:0 15: uart:unknown port:00000000 irq:0 16: uart:unknown port:00000000 irq:0 17: uart:unknown port:00000000 irq:0 18: uart:unknown port:00000000 irq:0 19: uart:unknown port:00000000 irq:0 20: uart:unknown port:00000000 irq:0 21: uart:unknown port:00000000 irq:0 22: uart:unknown port:00000000 irq:0 23: uart:unknown port:00000000 irq:0 24: uart:unknown port:00000000 irq:0 25: uart:unknown port:00000000 irq:0 26: uart:unknown port:00000000 irq:0 27: uart:unknown port:00000000 irq:0 28: uart:unknown port:00000000 irq:0 29: uart:unknown port:00000000 irq:0 30: uart:unknown port:00000000 irq:0 31: uart:unknown port:00000000 irq:0 roger@roger-desktop:~$ sudo cat /etc/group|grep roger root:x:0:roger daemon:x:1:earlleen,roger adm:x:4:roger tty:x:5:earlleen,roger disk:x:6:roger news:x:9:earlleen,roger uucp:x:10:earlleen,roger proxy:x:13:roger dialout:x:20:roger,earlleen fax:x:21:roger,earlleen voice:x:22:earlleen,roger cdrom:x:24:roger floppy:x:25:roger,earlleen sudo:x:27:roger audio:x:29:pulse,roger dip:x:30:roger,earlleen www-data:x:33:roger operator:x:37:roger irc:x:39:earlleen,roger utmp:x:43:roger video:x:44:roger,earlleen plugdev:x:46:roger users:x:100:earlleen,roger fuse:x:104:roger scanner:x:107:roger,earlleen lpadmin:x:109:roger netdev:x:113:roger roger:x:1000:roger sambashare:x:124:roger earlleen:x:1001:earlleen,roger clamav:x:126:earlleen,roger roger@roger-desktop:~$ roger@roger-desktop:~$ sudo which cu [sudo] password for roger: /usr/bin/cu roger@roger-desktop:~$ roger@roger-desktop:~$ cu -l /dev/ttyS0 -s 115200 Connected. cu: Got hangup signal Disconnected. roger@roger-desktop:~$ CLOSE AND REOPEN TERMINAL roger@roger-desktop:~$ cu -l /dev/ttyS4 -s 115200 Connected. roger@roger-desktop:~$ ls STRACE_CU.* STRACE_CU.17256 STRACE_CU.17257 roger@roger-desktop:~$ roger@roger-desktop:~$ cat STRACE_CU.*|grep EPERM roger@roger-desktop:~$ roger@roger-desktop:~$ cu -l /dev/ttyS4 -s 115200 --debug all cu: fconn_open: Opening port /dev/ttyS4 (speed 115200) cu: fconn_set: Changing setting to 0, 0, 2 Connected. roger@roger-desktop:~$ cu -l /dev/ttyS4 -s 115200 --debug all cu: fconn_open: Opening port /dev/ttyS4 (speed 115200) cu: fconn_set: Changing setting to 0, 0, 2 Connected. cu: fconn_write: Writing 1 "l" cu: fconn_write: Writing 1 "s" cu: fconn_write: Writing 1 " " cu: fconn_write: Writing 1 "S" cu: fconn_write: Writing 1 "T" cu: fconn_write: Writing 1 "R" cu: fconn_write: Writing 1 "A" cu: fconn_write: Writing 1 "C" cu: fconn_write: Writing 1 "E" cu: fconn_write: Writing 1 "_" cu: fconn_write: Writing 1 "C" cu: fconn_write: Writing 1 "U" cu: fconn_write: Writing 1 "." cu: fconn_write: Writing 1 "*" roger@roger-desktop:~$ ls STRACE_CU.* STRACE_CU.17256 STRACE_CU.17715 STRACE_CU.17720 STRACE_CU.17914 STRACE_CU.17257 STRACE_CU.17716 STRACE_CU.17721 STRACE_CU.17915 roger@roger-desktop:~$ SEGMENT OF 17256 ioctl(3, TIOCNOTTY) = -1 ENOTTY (Inappropriate ioctl for device) close(3) = 0 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 nanosleep({2, 0}, 0x7fff8df7f520) = 0 unlink("/var/lock/LCK..ttyS0") = 0 write(1, "\n", 1) = 1 write(1, "\7Disconnected.\n", 15) = 15 exit_group(0) = ? roger@roger-desktop:~$ roger@roger-desktop:~$ cat STRACE_CU.17257 close(4) = 0 fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE) fcntl(3, F_SETFL, O_RDWR|O_LARGEFILE) = 0 rt_sigaction(SIGUSR1, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 rt_sigaction(SIGUSR2, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 rt_sigaction(SIGINT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 rt_sigaction(SIGQUIT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 rt_sigaction(SIGPIPE, {SIG_DFL, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 rt_sigaction(SIGTERM, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7f3a954a34a0}, NULL, 8) = 0 read(3, 0x7fff8df7f110, 1024) = -1 EIO (Input/output error) getppid() = 17256 kill(17256, SIGHUP) = 0 exit_group(0) = ? roger@roger-desktop:~$ SEGMENT OF ???????????? LOTS OF THESE close(997) = -1 EBADF (Bad file descriptor) close(998) = -1 EBADF (Bad file descriptor) close(999) = -1 EBADF (Bad file descriptor) close(1000) = -1 EBADF (Bad file descriptor) close(1001) = -1 EBADF (Bad file descriptor) close(1002) = -1 EBADF (Bad file descriptor) close(1003) = -1 EBADF (Bad file descriptor) close(1004) = -1 EBADF (Bad file descriptor) ... ONE OF THESE rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 nanosleep({2, 0}, 0x7fff4a077230) = 0 unlink("/var/lock/LCK..ttyS0") = 0 roger@roger-desktop:~$ cat STRACE_CU.17716 close(4) = 0 fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE) fcntl(3, F_SETFL, O_RDWR|O_LARGEFILE) = 0 rt_sigaction(SIGUSR1, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 rt_sigaction(SIGUSR2, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 rt_sigaction(SIGINT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 rt_sigaction(SIGQUIT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 rt_sigaction(SIGPIPE, {SIG_DFL, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 rt_sigaction(SIGTERM, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fd4cf15c4a0}, NULL, 8) = 0 read(3, 0x7fff4a076e20, 1024) = -1 EIO (Input/output error) getppid() = 17715 kill(17715, SIGHUP) = 0 exit_group(0) = ? roger@roger-desktop:~$ roger@roger-desktop:~$ cat STRACE_CU.17915 close(4) = 0 fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE) fcntl(3, F_SETFL, O_RDWR|O_LARGEFILE) = 0 rt_sigaction(SIGUSR1, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 rt_sigaction(SIGUSR2, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 rt_sigaction(SIGINT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 rt_sigaction(SIGQUIT, {SIG_IGN, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 rt_sigaction(SIGPIPE, {SIG_DFL, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 rt_sigaction(SIGTERM, {0x409f70, [], SA_RESTORER|SA_INTERRUPT, 0x7fbd2e8714a0}, NULL, 8) = 0 read(3, 0x7fff7f3b4840, 1024) = -1 EIO (Input/output error) getppid() = 17914 kill(17914, SIGHUP) = 0 exit_group(0) = ? roger@roger-desktop:~$ sudo uname -aModem info: description: Serial controller product: 56K FaxModem Model 5610 vendor: 3Com Corp, Modem Division physical id: 1 bus info: pci@0000:04:01.0 version: 01 width: 32 bits clock: 33MHz capabilities: pm 16550 cap_list configuration: driver=serial latency=0 resources: irq:17 ioport:d000(size=8 ) roger@roger-desktop:~$ sudo wvdialconf [sudo] password for roger: Editing `/etc/wvdial.conf'. Scanning your serial ports for a modem. Modem Port Scan<*1>: S0 S1 S2 S3 ttyS4<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud [ 1.365228] 0000:04:01.0: ttyS4 at I/O 0xd000 (irq = 17) is a 16550A ttyS4<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 115200 baud ttyS4<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up. Modem Port Scan<*1>: S5 S6 S7 S8 Modem Port Scan<*1>: S9 S10 S11 S12 S13 S14 S15 S16 Modem Port Scan<*1>: S17 S18 S19 S20 S21 S22 S23 S24 Modem Port Scan<*1>: S25 S26 S27 S28 S29 S30 S31 Sorry, NO MODEM WAS DETECTED! Is it in use by another program? - ( my caps ) Did you configure it properly with setserial?