03-01-2012 12:25 PM - edited 03-17-2019 10:52 PM
Hello everyone!
I am experiencing some issues when working with T.38 Fax in my network. I am simply unable to send / receive any faxes. The topology is quite simple:
Branch VoIP Router --> Central VoIP Router --> E1s to Alcatel PBX --> PSTN
The Branch voip router is able to send and receive phone calls normally, passing through the central VoIP router, which has E1 interfaces in order to send those phone calls to the Alcatel PBX that offers the connectivity to the PSTN services.
When a fax machine connected to the Branch VoIP router sends faxes to a remote fax machine, the remote fax machine rings and answers the call, but the fax transmission is then aborted. I've tried different remote fax machines and none worked, either when sending or receiving faxes.
With reference to Phone calls, everything works perfectly. My only issue here is when trying to send/receive faxes. I am enclosing my configuration below:
card type e1 1 1
!
network-clock-participate slot 1
!
isdn switch-type primary-qsig
!
voice-card 0
dspfarm
!
voice-card 1
dspfarm
!
voice call send-alert
!
controller E1 1/0
clock source line primary
pri-grouptimeslots 1-31
!
controller E1 1/1
pri-group timeslots 1-31
!
interface Serial1/0:15
noip address
encapsulationhdlc
isdnswitch-type primary-qsig
isdntimer T310 120000
isdnprotocol-emulate network
isdnincoming-voice voice
no cdp enable
!
interface Serial1/1:15
noip address
encapsulationhdlc
isdnswitch-type primary-qsig
isdntimer T310 120000
isdnprotocol-emulate network
isdn incoming-voice voice
no cdp enable
!
voice-port 1/0:15
no non-linear
novad
playout-delaynominal 100
playout-delayfax 100
playout-delaymode fixed
bearer-capSpeech
!
voice-port 1/1:15
no non-linear
novad
playout-delaynominal 100
playout-delayfax 100
playout-delaymode fixed
bearer-cap Speech
!
mgcpfax t38 gateway force
!
dial-peervoice 73 voip
destination-pattern 059[1-8]
sessiontarget ipv4:172.16.1.0.10
dtmf-relayh245-signal
fax-relay ecm disable
fax rate 7200
fax nsf 000000
faxprotocol t38 nse version 0 ls-redundancy 0 hs-redundancy 0 fallback none
!
Does any one have a suggestion here?
Thank you!
Leo
card type e1 1 1
!
network-clock-participate slot 1
!
isdn switch-type primary-qsig
!
voice-card 0
dspfarm
!
voice-card 1
dspfarm
!
voice call send-alert
!
controller E1 1/0
clock source line primary
pri-grouptimeslots 1-31
!
controller E1 1/1
pri-group timeslots 1-31
!
interface Serial1/0:15
noip address
encapsulationhdlc
isdnswitch-type primary-qsig
isdntimer T310 120000
isdnprotocol-emulate network
isdnincoming-voice voice
no cdp enable
!
interface Serial1/1:15
noip address
encapsulationhdlc
isdnswitch-type primary-qsig
isdntimer T310 120000
isdnprotocol-emulate network
isdn incoming-voice voice
no cdp enable
!
voice-port 1/0:15
no non-linear
novad
playout-delaynominal 100
playout-delayfax 100
playout-delaymode fixed
bearer-capSpeech
!
voice-port 1/1:15
no non-linear
novad
playout-delaynominal 100
playout-delayfax 100
playout-delaymode fixed
bearer-cap Speech
!
mgcpfax t38 gateway force
!
dial-peervoice 73 voip
destination-pattern 059[1-8]
sessiontarget ipv4:192.168.0.10
dtmf-relayh245-signal
fax-relay ecm disable
fax rate 7200
fax nsf 000000
faxprotocol t38 nse version 0 ls-redundancy 0 hs-redundancy 0 fallback none
!
03-04-2012 04:16 PM
Is T.38 configured on both the branch and central router? Since you have configured it on a specific dial-peer instead of globally (voice service voip) have you confirmed that those voip dial-peers are being matched on both routers for the call? When the DSP of one router detects the fact tones it initiates a T.38 switchover; both routers must be configured for this to work.
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