For configuration you can refer to the following 2 links
Configure Cisco IP Phones with Asterisk
Cisco IP Phones 79XX with Asterisk
Here is the sample configuration for both 7940 and 7911
in this sample we assume that:
Asterisk IP: 192.168.1.200
SIP Extension: 107
Password: 123456
Here is the tftp log for 7911:
Connection received from 192.168.1.30 on port 49160 [23/11 18:02:45.340] Read request for file <SIP42.8-5-3S.loads>. Mode octet [23/11 18:02:45.370] Using local port 1052 [23/11 18:02:45.380] <SIP42.8-5-3S.loads>: sent 2 blks, 668 bytes in 0 s. 0 blk resent [23/11 18:02:45.440] Connection received from 192.168.1.30 on port 49161 [23/11 18:02:46.672] Read request for file <jar42sip.8-5-3TH1-6.sbn>. Mode octet [23/11 18:02:46.702] Using local port 1053 [23/11 18:02:46.712] <jar42sip.8-5-3TH1-6.sbn>: sent 3435 blks, 1758418 bytes in 5 s. 0 blk resent [23/11 18:02:51.659] Connection received from 192.168.1.30 on port 49162 [23/11 18:02:56.836] Read request for file <cnu42.8-5-3TH1-6.sbn>. Mode octet [23/11 18:02:56.867] Using local port 1054 [23/11 18:02:56.877] <cnu42.8-5-3TH1-6.sbn>: sent 1026 blks, 524917 bytes in 2 s. 0 blk resent [23/11 18:02:58.869] Connection received from 192.168.1.30 on port 49163 [23/11 18:03:01.133] Read request for file <apps42.8-5-3TH1-6.sbn>. Mode octet [23/11 18:03:01.163] Using local port 1055 [23/11 18:03:01.173] <apps42.8-5-3TH1-6.sbn>: sent 5735 blks, 2935993 bytes in 8 s. 0 blk resent [23/11 18:03:09.425] Connection received from 192.168.1.30 on port 49164 [23/11 18:03:17.306] Read request for file <dsp42.8-5-3TH1-6.sbn>. Mode octet [23/11 18:03:17.326] Using local port 1056 [23/11 18:03:17.326] <dsp42.8-5-3TH1-6.sbn>: sent 666 blks, 340615 bytes in 1 s. 0 blk resent [23/11 18:03:18.377] Connection received from 192.168.1.30 on port 49165 [23/11 18:03:20.140] Read request for file <cvm42sip.8-5-3TH1-6.sbn>. Mode octet [23/11 18:03:20.180] Using local port 1057 [23/11 18:03:20.190] <cvm42sip.8-5-3TH1-6.sbn>: sent 4862 blks, 2489011 bytes in 8 s. 0 blk resent [23/11 18:03:28.182] Connection received from 192.168.1.30 on port 49166 [23/11 18:04:22.780] Read request for file <CTLSEPD4D748412EC9.tlv>. Mode octet [23/11 18:04:22.820] File <CTLSEPD4D748412EC9.tlv> : error 2 in system call CreateFile The system cannot find the file specified. [23/11 18:04:22.830] Connection received from 192.168.1.30 on port 49167 [23/11 18:04:22.970] Read request for file <SEPD4D748412EC9.cnf.xml>. Mode octet [23/11 18:04:23.010] Using local port 1059 [23/11 18:04:23.010] <SEPD4D748412EC9.cnf.xml>: sent 1 blk, 129 bytes in 1 s. 0 blk resent [23/11 18:04:23.060]
And this is tftp log for 7940:
Previously allocated address 192.168.1.10 acked [16/01 13:26:12.051] Connection received from 192.168.1.10 on port 52789 [16/01 13:26:12.111] Read request for file <SIPDefault.cnf>. Mode octet [16/01 13:26:12.131] Using local port 2845 [16/01 13:26:12.131] <SIPDefault.cnf>: sent 4 blks, 1792 bytes in 0 s. 0 blk resent [16/01 13:26:12.192] Connection received from 192.168.1.10 on port 52790 [16/01 13:26:12.432] Read request for file <./SIP001759E55CD0.cnf>. Mode octet [16/01 13:26:12.462] Using local port 2846 [16/01 13:26:12.472] <.\SIP001759E55CD0.cnf>: sent 2 blks, 903 bytes in 0 s. 0 blk resent [16/01 13:26:12.502] Connection received from 192.168.1.10 on port 52794 [16/01 13:26:14.895] Read request for file <RINGLIST.DAT>. Mode octet [16/01 13:26:14.905] File <RINGLIST.DAT> : error 2 in system call CreateFile The system cannot find the file specified. [16/01 13:26:14.905] Connection received from 192.168.1.10 on port 52795 [16/01 13:26:15.156] Read request for file <dialplan.xml>. Mode octet [16/01 13:26:15.166] Using local port 2848 [16/01 13:26:15.166] <dialplan.xml>: sent 1 blk, 91 bytes in 0 s. 0 blk resent [16/01 13:26:15.206]