Comment 11 for bug 282207

No the problem is not the it is using ttyUSB0. This is what the ppp scripts from Sierra wireless use. The problem is the spaces used in the APN setting line. As in my patch above once I took out the spaces it just worked!

This is exactly how it is done in the Sierra PPP scripts and any other dialer (kppp) to get the Sierra Wireless 881 (or any other) going. See script "peers/gsm". The Sierra PPP scripts can be found here:
http://www.sierrawireless.com/faq/ShowFAQ.aspx?ID=601

Here is the patch again that fixes the problem, rebuilding network manager with this patch things just work:
Signed-off-by: Jerone Young <email address hidden>

=== modified file 'src/nm-gsm-device.c'
--- src/nm-gsm-device.c 2008-10-22 03:24:00 +0000
+++ src/nm-gsm-device.c 2008-10-22 03:24:39 +0000
@@ -213,7 +213,7 @@
   return;
  }

- command = g_strdup_printf ("AT+CGDCONT=%d, \"IP\", \"%s\"", cid, setting->apn);
+ command = g_strdup_printf ("AT+CGDCONT=%d,\"IP\",\"%s\"", cid, setting->apn);
  modem_wait_for_reply (device, command, 7, responses, responses, set_apn_done, GUINT_TO_POINTER (cid));
  g_free (command);
 }