Two serial connections into one, transport, then split again

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Re: Two serial connections into one, transport, then split a

Post by dbuckley »

That explains an oddity in the block diagram, the two serial ports have different data paths.
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Location: Hastings, Ne

Re: Two serial connections into one, transport, then split a

Post by themarcshow »

Hey all,
Thanks so much for the discussion. I've been deep in other stuff this past week so I'm sorry I haven't replied promptly.
I think that Dave K summed up my situation best:
davek wrote:If the encoder/decoder pair was only specified to be a 2 channel unit, then the parts required to operate in 4 channel mode may not have been installed (off memory this includes 2 aptX chips, another large PLCC chip and some other miscellaneous parts). This may be the situation the OP is in - he can't enable the second data channel.

To enable the second data channel, the encoder/decoder will have to be converted and configured to operate as 4 channel units. Doing this is not as straightforward as it seems (refer to my earlier post). It requires either a wider STL channel, or converting the encoder/decoder to use high-efficiency mode (assuming the path is clean and there is plenty of RX signal).
And it was mentioned I may have left out some details in my other posts so here is the 'full picture'
L/R audio and 300baud serial on Data port 1 goes into a Mosley 6000A encoder.
Encoded signal goes into the COMP input of a Mosley 6010 STL Transmitter

It is received by a 6020 Mosley STL Receiver and decoded by as 6000D decoder
I think I’m running at total data rate of 256kbps

As noted in the manual- Data 2 cannot be turned off, however it’s not active in all transmission modes
Data Channel 2 (DATA 2) is an asynchronous RS-232 port. This data is multiplexed with
the MAIN and AUX audio data. DATA 2 is available only in 3 and 4 channel
configurations, and is always active in these configurations. It may not be disabled

Data channels DATA 1 and DATA 2 are asynchronous DCE ports capable of baud rates of 300, 1200, 2400, and 4800 baud. In addition, DATA 2 is capable of 9600 baud in some
configurations. Factory default is 1200 baud.

The DSP6000A can transmit up to two asynchronous data channels. The ports are wired
as Data Communication Equipment (DCE). Data Channel 1 (DATA 1) uses one bit (the
LSB) from the MAIN LEFT APTx encoder/decoder pair. This channel can be switched on or off. DATA 2 is multiplexed with the MAIN and AUX audio data within the auxiliary multiplexer, and cannot be disabled. Table 5-16 and Table 5-17 show the DIP switch settings for the two data channels.
The channel mode I’m running has 2, 15khz audio channels and only data port 1
Ch Mode 2 2 x 15 kHz & 1 x 4.8 kbps

Which all comes back to my original desire to mux the two serial connections into one for the encoder.

I think my next step will be trying to run in High Efficiency mode over a 25 mile link. That might be interesting.

Again, thanks for all the advice.
Brad Beahm
Operations Manager Platte River Radio
Hastings, Ne
Posts: 35
Joined: Wed Aug 01, 2012 2:33 pm

Re: Two serial connections into one, transport, then split a

Post by AltheEngineer »

In the good old days of the BT AT1616 controller card they could be addressed by the program on the computer to allow parallel operation with one serial port. But it had to be the same speed etc and I doubt there is a program to combine them into one stream on a computer in the studio. The black box may be the answer. I also remember the DSP6000 only being able to handle up to one mono, one stereo and then two serial. With two stereo the extra serial port was disabled. And that was with a 4 channel unit.
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