[Serusers] 183 session progress

[Jorge Crichigno]

I have a doubt with a scenario, where a call is done between two
APX/MAX-TNT Lucent Gateways(GW):

       Gw A	       SER 	        GW B
	|   INVITE->	|		|	
PSTN A	|    <-100	|		|   PSTN B side
side	|		|   INVITE->	|
	|		|   <-183 w/SDP	|
	|  <-183 w/SDP	|		|
	|		|		|
	|		|		|

Then, the call downs by some reason as timeout. I just don't understand
well the meaning of 183. AFAIK, when it happens, it should or could be
an 'early' rtp flow from B that should be audible for A (for example, A
could expect a play message from PSTN B side operator). Is that correct?
Could someone clarify me this concept? 

 Thank you!

PS: does someone use ever APX/MAX-TNT Lucent gateways? I have some
doubts about his configuration.


                            Jorge