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Problem with Drop and Insert

Hi all

I am configuring "Drop and Insert" in VWIC2-2MFT-T1/E1 on router 3845.My topo follos: PBX--R3845---Wan(voice and data)---R3845---PBX.

After configuring, Voice and data is OK. I can make a phone call and ping successfully. But Fax and Modem analog do not work. I don't know why?

Please help me.

thank.

5 Replies 5

paolo bevilacqua
Hall of Fame
Hall of Fame

Hi,

Hi, check out, there is special configuration to make fax/modem work reliably over VoIP, namely fax and modem relay. Just search CCO and begin reading.

Note: this is not really Drop & Insert application.

Hi p.bevilacqua.

I think you don't understand my idea. The 3845 Routers are connected to Switchs. I used 15 channels for Voice and 15 channel for Data in WAN link.

Detail about my topo:

PBX---R3845---Wan---R3845--PBX.

..............|..........................|

...........SW.......................SW

I configured Drop and insert in VWIC2 on 3845Routers. One VWIC connects to PBX, the other connects WAN.

Sample configure file in a R3845:

controller E1 0/0/0

framing NO-CRC4

ds0-group 0 timeslots 9-15,25-31 type e&m-wink-start dtmf dnis

tdm-group 1 timeslots 1-8,17-24 type e&m

description Tuyen E1 tra ve Tong dai

!

controller E1 0/0/1

framing NO-CRC4

clock source internal

channel-group 0 timeslots 9-15,25-31

tdm-group 1 timeslots 1-8,17-24 type e&m

description Tuyen E1 di DN

!

connect TDM_to_Data_DN E1 0/0/0 1 E1 0/0/1 1

interface Serial0/0/1:0

description Ket noi den trung tam vung Da Nang

ip address 10.64.253.81 255.255.255.252

!

Hi,

Could be a clocking problem, please send "show controllers e1" and check inf PBX and SW wants internal or external clock.

you wiol need "network-clocks-participate" and network-clocks-select" to define how you are using clock in this design. Likely, source from the E1 circuit and give to PBX and switches.

Hi p.bevilacqua.

In R3845, The E1 port ,Which connects PBX , is set Clock source internal. The other(to WAN) is set clock source line. I also used "network-clock-participate wic 0" .

I think If clock encounter problem , I can't ping Successfully and make a phone call.

Please,Give me more your ideas about this.

Thanks.

well, if the problem with modem and fax happens to on the PBX that are using VoIP, as I said initially you must do special configuration, T.38 for tax, and modem realy for modem. In any case, check "show controller e1" for slips.

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