Rhino 8 Port FXO EC

General Help
1

Having problems with a Rhino 8 Port FXO EC card. The EC is taking up to 30 seconds to tune itself for a phone call. In the meantime, my users have scratchy/windy sounds in their ears.

Rhino is very S L O W to respond.

Reading various message boards, it is suggested to run fxotune, but when I do that I get the following:
Failed to open /dev/dahdi/ctl: No such file or directory

I’m about ready to just order another FXO card, but want to give the Rhino one last try before I abandon it.

Thanks,
Westley

2

Do you still have no_ec set (from your previous forum post) ?

If so you are not using the hardware EC

3

You can’t run fxotune unless dahdi is running.

4

(neither can you run fxotune unless asterisk is stopped, they are not the same thing)

5

No, I’ve got the hardware EC working now. The last series is where I discovered the hwec wasn’t even on. Now it is confirmed thru dahdi_cfg output.

I finally got fxotune to run. So many help files say to stop asterisk but almost none of them tell you to manually start dahdi afterwards.

Unfortunately, it doesn’t seem to have helped. Now the scratchy noise is lasting way past 60 seconds.

Will play with it a bit more tonight.

Thanks,
Westley

6

you should ideally run fxotune with HWEC off in the dahdi driver.

7

And then check your rx/tx gains preferably with milliwatt testing and dahdi_monitor.

8

(if you want your HWEC to “converge” quickly)

9

If your trunks are markedly different you might need to set rx/tx gains individually on each channel, be patient here, it’s worth the effort . . .

10

I turned off the hwec and reran fxotune. So that I could get a better handle on what it was reporting, I ran it on each channel separately and then ran it on all six channels being used together.

Below is the output. At the end, is a file named fxotune.1, that was the settings fxotune picked when I ran it with hwec turned on.

I haven’t been able to find a milliwatt number yet to really look at the gains, but they seem to be ok for the most part.

Thanks,
Westley

Config with lowest response = 57, magnitude = 0, echo = -87.7978 dB
Top 5 results for Acim2_tune Test
Res #1: index=57, 7,255,255,255,255, 0, 0, 0, 0: magnitude = 0, echo = -87.7978 dB
Res #2: index=58, 9, 0,253,254, 2,255, 0, 0, 0: magnitude = 0, echo = -86.9278 dB
Res #3: index=44, 5,252,250, 1, 1,254, 0,255,255: magnitude = 0, echo = -85.2450 dB
Res #4: index=52, 5,252,250, 0, 0,254, 0,255, 0: magnitude = 0, echo = -85.0480 dB
Res #5: index=56, 7, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 0, echo = -84.7734 dB
Done!
Found best echo coefficients: 8=7,255,255,255,255,0,0,0,0

fxotune: set channel 8
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 70, magnitude = 1, echo = -84.1095 dB
Top 5 results for Acim2_tune Test
Res #1: index=70, 14, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -84.1095 dB
Res #2: index=53, 5, 3,251,250, 2,253,255,255,254: magnitude = 1, echo = -84.0366 dB
Res #3: index=54, 3, 1, 1,242, 2, 9,245, 3,253: magnitude = 1, echo = -83.4571 dB
Res #4: index=43, 9, 2,250,253, 4,252, 0,255,255: magnitude = 1, echo = -83.0381 dB
Res #5: index=44, 5,252,250, 1, 1,254, 0,255,255: magnitude = 1, echo = -82.1472 dB
Done!
Found best echo coefficients: 7=14,0,0,0,0,0,0,0,0

fxotune: set channel 7
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 7, magnitude = 0, echo = -89.1452 dB
Top 5 results for Acim2_tune Test
Res #1: index=7, 10,249,244, 8, 12,245,252, 0, 1: magnitude = 0, echo = -89.1452 dB
Res #2: index=1, 10, 0, 6, 1,254, 2,255, 0, 0: magnitude = 0, echo = -87.6069 dB
Res #3: index=2, 3,255,255, 0, 1, 0, 0, 0, 0: magnitude = 0, echo = -85.9568 dB
Res #4: index=3, 3, 1,253,253, 2,255, 0, 0, 0: magnitude = 0, echo = -85.6673 dB
Res #5: index=4, 9,254,251,255, 2, 0, 1, 0, 0: magnitude = 1, echo = -82.9894 dB
Done!
Found best echo coefficients: 6=10,249,244,8,12,245,252,0,1

fxotune: set channel 6
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 25, magnitude = 1, echo = -80.6150 dB
Top 5 results for Acim2_tune Test
Res #1: index=25, 7, 0,255,254,255, 0,255, 0, 0: magnitude = 1, echo = -80.6150 dB
Res #2: index=56, 7, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -80.5948 dB
Res #3: index=49, 6, 1,254,253, 0,255, 0, 0, 0: magnitude = 1, echo = -80.0224 dB
Res #4: index=48, 6, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -78.8674 dB
Res #5: index=52, 5,252,250, 0, 0,254, 0,255, 0: magnitude = 1, echo = -78.1562 dB
Done!
Found best echo coefficients: 6=7,0,255,254,255,0,255,0,0

fxotune: set channel 6
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 25, magnitude = 0, echo = -87.2119 dB
Top 5 results for Acim2_tune Test
Res #1: index=25, 7, 0,255,254,255, 0,255, 0, 0: magnitude = 0, echo = -87.2119 dB
Res #2: index=19, 5, 1,249,254, 4,253, 1, 0, 0: magnitude = 0, echo = -86.8107 dB
Res #3: index=46, 3, 1, 1,242, 2, 9,245, 3,253: magnitude = 0, echo = -86.3026 dB
Res #4: index=61, 5, 3,251,250, 2,253,255,255,255: magnitude = 0, echo = -86.1478 dB
Res #5: index=15, 10,249,244, 8, 12,245,252, 0, 1: magnitude = 0, echo = -85.8389 dB
Done!
Found best echo coefficients: 5=7,0,255,254,255,0,255,0,0

fxotune: set channel 5
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 48, magnitude = 1, echo = -79.9715 dB
Top 5 results for Acim2_tune Test
Res #1: index=48, 6, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -79.9715 dB
Res #2: index=57, 7,255,255,255,255, 0, 0, 0, 0: magnitude = 1, echo = -79.3803 dB
Res #3: index=68, 12, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -78.8592 dB
Res #4: index=65, 9, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -77.0557 dB
Res #5: index=41, 9, 0,255, 1,255,255, 0,255, 0: magnitude = 1, echo = -76.7926 dB
Done!
Found best echo coefficients: 4=6,0,0,0,0,0,0,0,0

fxotune: set channel 4
fxotune: successfully set echo coeffecients on FXO modules

Config with lowest response = 26, magnitude = 0, echo = -85.3104 dB
Top 5 results for Acim2_tune Test
Res #1: index=26, 9, 0,253,253, 1,255, 0, 0, 0: magnitude = 0, echo = -85.3104 dB
Res #2: index=47, 10,249,244, 8, 12,245,252, 0, 1: magnitude = 0, echo = -85.0249 dB
Res #3: index=49, 6, 1,254,253, 0,255, 0, 0, 0: magnitude = 0, echo = -84.9401 dB
Res #4: index=42, 5,255,252, 0, 2,254, 0,255,255: magnitude = 0, echo = -84.6725 dB
Res #5: index=48, 6, 0, 0, 0, 0, 0, 0, 0, 0: magnitude = 1, echo = -84.1062 dB
Done!
Found best echo coefficients: 3=9,0,253,253,1,255,0,0,0

fxotune: set channel 3
fxotune: successfully set echo coeffecients on FXO modules

[root@localhost dahdi]# cat /etc/fxotune.conf
3=10,249,244,8,12,245,252,0,1
4=5,252,250,0,0,254,0,255,0
5=8,253,2,244,255,10,244,3,253
6=3,0,0,0,0,0,0,0,0
7=5,252,250,1,1,254,0,255,255
8=5,1,249,254,3,253,1,0,0

[root@localhost dahdi]# cat /etc/fxotune.1
3=5,252,250,0,0,254,0,255,0
4=9,0,253,254,2,255,0,0,0
5=10,249,244,8,12,245,252,0,1
6=5,252,250,1,1,254,0,255,0
7=5,1,249,254,3,253,1,0,0
8=9,0,253,254,2,255,0,0,0

11

Thanks to another englishman’s effort:-

http://www.freepbx.org/comment/210832#comment-210832

Here is how it works, fxotune tunes the 2-4 wire hybrid to match the complex impedance on the PSTN and how the rx/tx is balanced through the hybrid, matching the gain makes that easier, so reiterate the process, when all is optimized then echocancelers using another FFT in the time domain can sample the “FFT taps” and correct the signal in a sub-audible fashion, IMHO oslec as a software solution is often as effective as a HWEC when so balanced without too much CPU overhead, but if if you have paid for the HWEC then use it.