Bellow is the relevant debug log with dtmf logging:
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033731, ts 013784, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010083, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010083, ts 93763233, len 000004, mark 1, event 0000000a, end 0, duration 00000)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] DTMF[19583][C-00000005] channel.c: DTMF begin ‘’ received on SIP/9111-00000007
[2017-06-01 17:18:13] DTMF[19583][C-00000005] channel.c: DTMF begin passthrough '’ on SIP/9111-00000007
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021252, ts 016320, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001953, ts 015128, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030362, ts 015112, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033732, ts 013944, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010084, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010084, ts 93763233, len 000004, mark 0, event 0000000a, end 0, duration 00160)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021253, ts 016480, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001954, ts 015288, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030363, ts 015272, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033733, ts 014104, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010085, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010085, ts 93763233, len 000004, mark 0, event 0000000a, end 0, duration 00320)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021254, ts 016640, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001955, ts 015448, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030364, ts 015432, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033734, ts 014264, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021255, ts 016800, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010086, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010086, ts 93763233, len 000004, mark 0, event 0000000a, end 0, duration 00480)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001956, ts 015608, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030365, ts 015592, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033735, ts 014424, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010087, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010087, ts 93763233, len 000004, mark 0, event 0000000a, end 0, duration 00640)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021256, ts 016960, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001957, ts 015768, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030366, ts 015752, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010088, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010088, ts 93763233, len 000004, mark 0, event 0000000a, end 1, duration 00720)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] DTMF[19583][C-00000005] channel.c: DTMF end ‘’ received on SIP/9111-00000007, duration 90 ms
[2017-06-01 17:18:13] DTMF[19583][C-00000005] channel.c: DTMF end accepted with begin '’ on SIP/9111-00000007
[2017-06-01 17:18:13] DTMF[19583][C-00000005] channel.c: DTMF end passthrough ‘*’ on SIP/9111-00000007
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033736, ts 014584, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021257, ts 017120, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010089, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010089, ts 93763233, len 000004, mark 0, event 0000000a, end 1, duration 00720)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001958, ts 015928, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030367, ts 015912, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 101, seq 010090, ts 93763233, len 000004)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP RFC2833 from 192.168.0.42:10316 (type 101, seq 010090, ts 93763233, len 000004, mark 0, event 0000000a, end 1, duration 00720)
[2017-06-01 17:18:13] DEBUG[19583][C-00000005] res_rtp_asterisk.c: - RTP 2833 Event: 0000000a (len = 4)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:16000 (type 09, seq 033737, ts 014744, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021258, ts 017280, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 00, seq 010091, ts 93764113, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:19190 (type 09, seq 015793, ts 017096, len 000160)
[2017-06-01 17:18:13] VERBOSE[19586][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.41:19190 (type 09, seq 001959, ts 016088, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.42:10316 (type 00, seq 030368, ts 016072, len 000160)
[2017-06-01 17:18:13] VERBOSE[19584][C-00000006] res_rtp_asterisk.c: Sent RTP packet to 192.168.0.41:16000 (type 09, seq 021259, ts 017440, len 000160)
[2017-06-01 17:18:13] VERBOSE[19583][C-00000005] res_rtp_asterisk.c: Got RTP packet from 192.168.0.42:10316 (type 00, seq 010092, ts 93764273, len 000160)