Asterisk interface with legacy PBX

hello pal

I have Panasonic Advance Hybrid KX-TA308 PBX and i want it to be place behind My Asterisk Server.
My Question is What is the Basic connection? Am i right with this ?

Asterisk 2 FXO<-------->Panasonic 2 EXT Jack (for inbound to panasonic ext from Asterisk)
Asterisk 2 FXS<-------->Panasonic 2 CO (for inbound to Asterisk exten and outside call from panasonic)

With this setup i am thinking that Panasonic locals could make a call to Asterisk locals and vice versa. pana locals could make an outbound call and avail features same with Asteisk locals.

The Asterisk would be the PSTN Gateway.

Please help


it really depends on how much you can program the pbx.

assuming its a typical hybrid system (not much), then you’d probably only want 1-3 CO ports connected to asterisk FXS ports for dialing out. then configure ring groups as needed… or even better it might have DXD (direct extension dialing) so asterisk can ring it (with callerid), then sendDTMF the destination or dest. ring group.

however if there is no DXD and you need to target calls specifically to one extension, you will need a FXO * to PBX extension link… so asterisk can dial extensions one at a time…

i believe it has DXD as i read the manual there are lot dialing features
such as touch tone, system speed dialing, personal speed dialing pickup dialing. even redialing features it has.

IF will connect …


PANA_EXT3 <-------- ?
PANA_EXT4 <-------- ?
*FXS4 <-------------- ?
*FXS5 <-------------- ?

  1. From Asterisk which channel i must dial from and ring either EXT3 or EXT4? is it one of FXS1-FXS3 or FXO1 or FXO2?
  2. From Panasonic which channel i must dial from and ring either FXS4 or FXS5?

Those are pretty basic features, DXD is much more advanced- with DXD the Panasonic will answer (on its own) an incoming call, and play a message asking the caller to enter their extension number (or playing a brief directory). It means the panasonic must have some kind of audio module built in to store the recording…

as for call flows-

from Panasonic to *- panasonic picks up one of its CO ports that’s on an * FXS port, and dials.

Asterisk to Panasonic- one of three ways

  1. (CO w/ DXD) Asterisk rings one of its FXS ports that is connected to a Panasonic CO port, sending caller id data. Panasonic picks up after 1st ring and CID, asterisk SendDTMF’s where it actually wants the call to go (extension or ring group). Panasonic rings the phones (presumably still w/ callerid) and call goes through.

  2. (CO no DXD) Each CO port is assigned to ring different phones. Asterisk sends the call (with caller id) to the port that rings the right phones. This can cause trouble if that port is in use. Or if there is only one group of phones that need to ring, Asterisk picks a port and rings it using zaptel group. While Asterisk is sending ringing, the panasonic phones ring, and when someone picks up the Pana the call goes through.

  3. (Dial By Extension) Asterisk picks up one of the Extension ports plugged into a * FXO port, and dials the target extension or ring group. The caller id will read as whatever extension * is plugged into.

We have 9 departments in our coumpany and i would like to assigned
Panasonic extensions starting from “1” that is 100-199 and the Asterisk extensions will start from 2,3,4,5,6,7,8 and 9. same with PANA
it has 3 digits local number.
Now, calling from Panasonic extensions i can dial out by pressing fisrt “9”+ phone number. my confusion is…what if i will call only the Asterisk locals (not dial out) from PANA is it possible dialing directly the number let us say "503"
or i must dial first “9”+503 which is very annoying i guess.?

First stage of this is to go to 4 digit extension numbers.

so ALL extensions start for example with a 2, so panas are 21xx aterisk 22xx to 29xx that leasve you room for feature codes routes and all the rest.

as for if you need 9+503 that depends on the panasonic. If it has dialplan ability then you won’t need 9+503…

what i would do- presumably the ‘dial-9’ type thing is in some way programmable, that is when you pick up the phone you get a panasonic dialtone, and it knows that if you push 9 it should connect you to a free outgoing line in a line pool.
Can you do this more than once? IE, push 8 and you are connected to a different group of lines? If so then that is your answer, pushing say 831 will pick up a line from a group and dial 31. Asterisk can compensate for this. This will need growing number of analog channels as you expand on the * side, as each new prefix number needs its own group of lines, but presumably by the time you have more than 100 new extens on * you will be able to start migrating off the panasonic PBX…

so its all about panasonic capability. i got the point if panasonic can dial out with “9” prefix i must try with 2-8 ot make a dial out to asterisk locals.

thanks for helping ill ask you again when i meet new problem