I’m using the UM175 model so your mileage may vary.
Note: Red Hat officially supports various DELL branded EVDO modems by default in 5.x (see release notes)
Insert the UM175 and make sure the system detects it.
Example:
shell>dmesg
usb 5-1: USB disconnect, address 3
usb 5-1: new full speed USB device using uhci_hcd and address 4
usb 5-1: configuration #1 chosen from 1 choice
cdc_acm 5-1:1.0: ttyACM0: USB ACM device <—— Note the cdc_acm driver was loaded for it and the device is under ttyACM0 (/dev/ttyACM0)
Unfortunately, I couldn’t figure out how to use NetworkManager under RHEL 5.3 (yet) so I reverted back to the standard “network” service instead.
Example: (You DO NOT need to do this if you’re NOT using NetworkManager)
shell> sudo /sbin/service NetworkManager stop
shell> sudo /sbin/chkconfig –level 2345 NetworkManager off
shell> sudo /sbin/chkconfig –level 2345 network on
shell> sudo /sbin/service network start
Then use the “system-config-network” utility (Under – System\Administration\Network )
1. Select the “Hardware” tab and click “New”
2. Select “Modem” as the hardware type.
Note: The above info from dmesg shows “ttyACM0″, this will NOT be listed in the “Modem Device” selection (at least under mine it wasn’t), so simply erase what’s there and type in “/dev/ttyACM0″ (no quotes). I left everything else the same and clicked “OK”.
3. Select the “Devices” tab and click “New” this will start a Wizard.
* Select “Modem” and click Forward.
* Fill in “Phone Number” with “#777″ (no quotes)
* Fill in “Provider Name” with whatever (I put Verizon)
* Fill in “Login Name” with “AREACODEYOURWIRELESS#@vzw3g.com” (no quotes)
* Fill in “Password” with “vzw” (no quotes)
* Click Forward and leave the defaults (DNS etc.)
4. Activate your new configuration (this will restart the network controls etc)
You may want/need to set various options under the ppp configuration (like auto start etc).
You should now be able to connect. Until someone posts how to get the NetworkManager working, you may want to create a shortcut of the “Network” applet on your Panel/Desktop. 
Note: There are various ways to skin this cat. I just posted the easiest way I could for the general “Desktop” usage. ;0)
Worked great! Thank you.
Just found your article and gave it a shot. Worked like a charm on the first try. Thanks for the write-up!
I’m running RHEL 5.5 with a Pantech UM175 and have been using your method for about a month now. Although it works well… I really missed using NetworkManager. So I did some hacking and found a way to get NetworkManager to recognize the UM175. Here is what I did:
1. plugin usb moden
2. /sbin/lsusb
Bus 002 Device 006: ID 106c:3714 Curitel Communications, Inc. PANTECH USB MODEM [UM175]
Note the ID 106c:3714
usb.product_id = 106c
usb.interface.number = 3714
3. edit /usr/share/hal/fdi/information/10freedesktop/10-nm-modem.fdi
Search for 106c (product_id)
The next few sections are different Pantech modems and will contain a line like this where int=”0xnnnn” is increasing
Add the following section while maintaining the increasing int sequence (probably at the end of the Pantech modems). Be sure to place this before the last closing
modem
IS-707-A
4. reboot
5. plugin usb modem and open NetworkManager
6. RMB Edit Connections… and goto Mobile Broadband tab
7. Click Add and select “Curitel PANTECH USB MODEM [UM175]”
8. check Connect automatically and enter:
Number #777
Username nnnnnnnnnn@vzw3g.com (replacing nnnnnnnnnn with the modem’s areacode and phone number)
Password vzw
9. Click Apply
You should now be good to go…
I hope this helps someone.
damn HTML…
Here is the added code again:
modem
IS-707-A
Thanks for the awesome tip!
Rats!
OK I give up… I’m not going to try and post the code again.
dbcooper – please email me and I’ll send you the added code.