Have you been able to get the internal modem in an IBM Thinkpad 600E to work under a "modern" distro such as FC4? Yes, I still have a good use for this modem. The modem with mwavem-2.0-1 (rpm) worked fine under FC2. I've used the MSDOS PS2 utility to verify and try various IRQ and I/O settings for both ttyS0 and ttyS1. The kernel module loads fine. setserial indicates the serial ports are fine - for example:

/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

service-mwavem-restart fails with "Starting Mwave Manager: [FAILED]", after which /var/log/messages contains:

Sep 20 07:48:28 lap mwavem: Initializing mwave manager...
Sep 20 07:48:28 lap mwavem: MwaveAPIInit - StartMwaveSubsystem failed
Sep 20 07:48:28 lap mwavem: ERROR initializing mwave manager...

Running the BIOS test feature on the modem and serial ports yields "OK". The permissions on /dev/ttySx seem fine, and a /dev/modem symlink has been set up that looks fine. The kernel is 2.6.11-1.1369_FC4. So it seems like the hardware is fine, the kernel module is fine, but the user space application can't run under FC4.

Addendum: Since experiencing the above, I have done a fresh install of FC5 and reinstalled the mwave rpm. Using PS2, the modem is now configued to be ttyS1. Same symptoms (except that no /dev/modem is created): module seems to load fine, serial port seems to be configured correctly, but Mwave Manager won't start. With all trace functions in mwavem.conf enabled, /var/log/messages shows:

Jan 14 19:35:54 lap kernel: serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt lpSectionName=DEBUG lpKeyName=MWWTT32_TRACE nDefault=0 lpFileName=0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt section_name [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey entered, lpKeyName MWWTT32_TRACE, lpSectionName [DEBUG], lpFileName 0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::getSection entered, lpSectionName [DEBUG], region 0xb7fa7000, file 0x80c7140
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, got lpSectionName [DEBUG] at index 0x80c71c1
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, exit section [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got lpKeyName MWWTT32_TRACE at index 0x80c72be
Jan 14 19:35:54 lap mwavem: mwmutil::getkey, 1st byte following key 3d
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got value 1 at index 0x80c72cc
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, exit value 1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt, keyValue=1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt retVal=1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt lpSectionName=DEBUG lpKeyName=MWM_BL nDefault=0 lpFileName=0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt section_name [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey entered, lpKeyName MWM_BL, lpSectionName [DEBUG], lpFileName 0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::getSection entered, lpSectionName [DEBUG], region 0xb7fa7000, file 0x80c7140
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, got lpSectionName [DEBUG] at index 0x80c71c1
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, exit section [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got lpKeyName MWM_BL at index 0x80c72ce
Jan 14 19:35:54 lap mwavem: mwmutil::getkey, 1st byte following key 3d
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got value 1 at index 0x80c72d5
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, exit value 1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt, keyValue=1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt retVal=1
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt lpSectionName=DEBUG lpKeyName=MWAVEM_TRACE nDefault=1 lpFileName=0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::GetPrivateProfileInt section_name [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey entered, lpKeyName MWAVEM_TRACE, lpSectionName [DEBUG], lpFileName 0xbff66f03
Jan 14 19:35:54 lap mwavem: mwmutil::getSection entered, lpSectionName [DEBUG], region 0xb7fa7000, file 0x80c7140
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, got lpSectionName [DEBUG] at index 0x80c71c1
Jan 14 19:35:54 lap mwavem: mwmutil::getSection, exit section [DEBUG]
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got lpKeyName MWAVEM_TRACE at index 0x80c72d7
Jan 14 19:35:54 lap mwavem: mwmutil::getkey, 1st byte following key 3d
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, got value 1 at index 0x80c72e4
Jan 14 19:35:54 lap mwavem: mwmutil::getKey, exit value 1
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileInt, keyValue=1
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileInt retVal=1
Jan 14 19:35:55 lap mwavem: Initializing mwave manager...
Jan 14 19:35:55 lap mwavem: mwaveapi::MwaveAPIInit calling StartMwaveSubsystem
Jan 14 19:35:55 lap mwavem: dspsrv::StartMwaveSubsystem entry
Jan 14 19:35:55 lap mwavem: dspsrv::StartMwaveSubsystem calling StartMwaveAPIServer
Jan 14 19:35:55 lap mwavem: dspsrv::StartMwaveAPIServer entry
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileString lpSectionName=STARTUP lpKeyName=DEVICE lpDefault=/dev/modems/mwave lpReturnedString=0xbff66400 nSize=32 lpFileName=0xbff66f03
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileString section_name [STARTUP]
Jan 14 19:35:55 lap mwavem: mwmutil::getKey entered, lpKeyName DEVICE, lpSectionName [STARTUP], lpFileName 0xbff66f03
Jan 14 19:35:55 lap mwavem: mwmutil::getSection entered, lpSectionName [STARTUP], region 0xb7fa7000, file 0x80c7140
Jan 14 19:35:55 lap mwavem: mwmutil::getSection, got lpSectionName [STARTUP] at index 0x80c7ec0
Jan 14 19:35:55 lap mwavem: mwmutil::getSection, exit section [STARTUP]
Jan 14 19:35:55 lap mwavem: mwmutil::getKey, got lpKeyName DEVICE at index 0x80c7ed6
Jan 14 19:35:55 lap mwavem: mwmutil::getkey, 1st byte following key 3d
Jan 14 19:35:55 lap mwavem: mwmutil::getKey, got value /dev/modems/mwave at index 0x80c7edd
Jan 14 19:35:55 lap mwavem: mwmutil::getKey, exit value /dev/modems/mwave
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileString, keyValue=/dev/modems/mwave
Jan 14 19:35:55 lap mwavem: mwmutil::GetPrivateProfileString lpReturnedString=/dev/modems/mwave cSize=17
Jan 14 19:35:55 lap mwavem: dspsrv::StartMwaveAPIServer opened mwave device hDrv ffffffff
Jan 14 19:35:55 lap mwavem: dspsrv::ManagerInit entry usNum 1 usNum_Total 1 DD 0
Jan 14 19:35:55 lap mwavem: dspsrv::ManagerInit return from AddRManagerTail prmgr=8e921e0
Jan 14 19:35:55 lap mwavem: dspsrv::ManagerInit calling AddRDspTail()
Jan 14 19:35:55 lap mwavem: dspsrv::ManagerInit AddRDspTail returns prdsp 8e92200
Jan 14 19:35:55 lap mwavem: dspsrv::ManagerInit entry calling ConfigureDsp prdsp 8e92200, DD 0, usNum-1 0
Jan 14 19:35:55 lap mwavem: dspsrv::ConfigureDsp entry prdsp 8e92200 usDD 0 usId 1
Jan 14 19:35:55 lap mwavem: dspcalle:spBIOS_Abilities entry prdsp 8e92200
Jan 14 19:35:55 lap mwavem: dspcalle:spBIOS_ABilities error DSP_INS_BUFFER
Jan 14 19:35:55 lap mwavem: dspcalle:spBIOS_Abilities entry prdsp 8e92200
Jan 14 19:35:55 lap mwavem: dspcalle:spBIOS_Abilities calling IOCTL
Jan 14 19:35:55 lap mwavem: dspcalle:spBIOS_Abilites return from ioctl ddrc ffffffff
Jan 14 19:35:55 lap mwavem: dspsrv::StartMwaveAPIServer return from ManagerInit ulRC f096
Jan 14 19:35:55 lap mwavem: dspsrv::StartMWaveAPIServer exit ulRC f096
Jan 14 19:35:55 lap mwavem: MwaveAPIInit - StartMwaveSubsystem failed
Jan 14 19:35:55 lap mwavem: ERROR initializing mwave manager...

For some reason, instances of a ":" and a "D" get replaced with an emoticon in the above.

Is Mwave Manager simply not compatible with FC4 and FC5?

Same symptoms (except that no /dev/modem is created)
Something about adding a rule in /etc/udev to create the /dev/modem link?

Thanks, unSpawn, for the tip. Alas, that did not work. I wrote udev rules that gave correct permissions to ttyS1 and established a "modem" symlink to it, and commented out the line in the mwavem startup script that directs the script to attempt to establish that symlink. Same /var/log/messages output when starting mwavem both via the startup script and manually. Other things to try?