8.0
AUDIO STREAMING
8.1
RADIO OVER IP (RIP) DATA FORMAT
RIP is the system by which the RX-400A provides real time streaming audio. The RIP
packets are sent from the radio via standard UDP packets. With each UDP packet
containing a descriptive header and audio data block. The RIP UDP Packet is based on
the Real Time Protocol (RTP). RTP is the format utilized by various commercial Voice
Over IP systems. The format of the data packet used for RIP is as follows:
Octet 0
Header Information
0x80 = RTP Format
Octet 1
Header Information Continued
0x50
Octet 2-3
RTP Sequence
0xnn 0xnn
Packet Counter (=last+1) used for verification of service
Octet 4-7
RTP TimeStamp
0xnn 0xnn 0xnn 0xnn
Time Counter (=last+64)
Octet 8-11 RTP Sync Source
0x45 0xmm 0xnn 0xoo
ID of the Radio (last 4 MAC digits)
The above octets were arranged so that a third party program that supports RTP audio
protocol could already use the packets from the RX-400A.
Additional header information is included that is specific to the RX-400A.
Octet 12-15
Sampling Frequency
0x00 0xmm 0xnn 0xoo
MSB first. e.g. if sampling frequency is 54081
the value returned would be 0x00 0x00 0xd3 0x41.
Because the RX400 sample rate is related to filter
selection this will change when filters are changed.
128 octets
Audio Data
0xnn…
The audio data samples are two octets long and there are 64 of
them.
Format is 2 octets per sample MSB first.
There are two commands to start and stop the RIP process.
Stop Ethernet RIPing *E0<cr>
Start Ethernet RIPing *E1<cr>
PN 74446
8-1
9.0
MAINTENANCE
