Specifications

Chapter 11 - Fax Transmission Clear Channel Fax
148
Mediatrix 4100
Clear Channel Fax
The Mediatrix 4100 can send faxes in clear channel. The following is a clear channel fax call flow:
Figure 30: Clear Channel Fax Call Flow
 To set clear channel fax transmission via codec negotiation:
1. Choose the codec you want to favour during negotiation in the dataIfCodecMediaTypeImageEnable
variable.
C
R
C
X
2
0
0
O
K
[…]
m=audio 5004 RTP/AVP 18
m=image 5004 RTP/AVP 0 8
C
R
C
X
2
0
0
O
K
[…]
m=audio 5006 RTP /AVP 18
m=image 5006 RTP/AVP 0 8
M
D
C
X
2
0
0
O
K
RTP=G.729 (Voice Call )
RTP=PCMU (Echo Cancellation + Silence Suppression = disabled )
No MDCX!!
• There is no need for a MDCX since the far end already supports the data codec (PCMU).
• When your SDP capabilities are inserted in a MGCP packet , it implies that you can receive any of these capabilities at any
given time without notice .
• In this case , both ends should switch to clear channel automatically upon detection of the fax transmission .
Fax is terminated
Fax Tone Detected
User Agent
#1
Call Agent
User Agent
#2
……...
…………..
……………….
……...
…………..
……………….
[…]
m=audio 5004 RTP/AVP 18
m=image 5004 RTP/AVP 0 8
[…]
m=audio 5006 RTP/AVP 18
m=image 5006 RTP/AVP 0 8
Table 109: Codec Negotiation Parameters
Parameter Description
disable The image media type is not present in the SDP.
pcmu The image media type is present in the SDP for PCMU only.
pcma The image media type is present in the SDP for PCMA only.