Hints on IRLP

In looking at the log file for our IRLP node, I have noticed that there have been a number of failed out-going IRLP attempts. They all seem to be caused by the same problem … poor DTMF tones.

Here’s how our node is set up:  When the controller detects a ‘#’, a script starts that reads and temporarily stores all subsequent tones. Once you release your Push-to-Talk, the controller re-generates what it heard and sends that to the IRLP node.

Here is an example of what the IRLP node heard:

A good connect:
Mar 27 2011 18:24:28 -0400 decode: DTMF = 9070
Mar 27 2011 18:24:31 -0400 Node Connected to reflector ref9070 on channel 0
Mar 27 2011 18:26:52 -0400 decode: DTMF = 73
Mar 27 2011 18:26:52 -0400 Node Disconnect from ref9070

A poor quality attempt; (Detected 2 different sets of numbers, maybe the PTT released between tones?)
Mar 28 2011 21:41:33 -0400 decode: DTMF = 51
Mar 28 2011 21:41:33 -0400 decode: Invalid command length: 51
Mar 28 2011 21:44:35 -0400 decode: DTMF = 41
Mar 28 2011 21:44:35 -0400 decode: Invalid command length: 41

Here’s an attempt where the signal was probably not strong enough, so each tone sounded like several tones:
Mar 29 2011 09:26:05 -0400 decode: DTMF = 9997772
Mar 29 2011 09:26:05 -0400 decode: Invalid command length: 9997772
Mar 29 2011 09:26:20 -0400 decode: DTMF = 999772
Mar 29 2011 09:26:20 -0400 decode: Invalid command length: 999772
Mar 29 2011 09:52:37 -0400 decode: DTMF = 92
Mar 29 2011 09:52:37 -0400 decode: Invalid command length: 92

Make sure that you send the ‘#’ and all the rest of the tones in one continuous sequence, without releasing your PTT.  If you drop the carrier between tones, all bets are off! Plus you do need a decent signal into the repeater.  A handheld in your basement likely won’t do it. Or if your signal into the repeater is ‘scratchy’, you probably won’t be able to connect.

It is probably a good practice to keep each DTMF tone short, giving less opportunity for multiple decoding of the tone.
Note that you do not need the ‘#’ when signing off – just send ’73’.

Cheers, and let me know how IRLP works for you, so we can fine tune it!

Bryan, VA3OG

Advertisements
This entry was posted in ARES, Club News, Repeater status. Bookmark the permalink.