reducing dialout delay on Obi110 over the LINE interface
lk96:
Hello:
I have a configuration where an Obi110 device sits between my home phone handset
and a Vonage adaptor. So the connectivity is like:
PHONE -> Obi110 -> Vonage adaptor
The line copper interface from the Obi is connected to the phone port coming off the Vonage adaptor.
This allows me to have all home calls routed by default through the Vonage service. But also to be able
to redirect specific calls/number to lower cost SIP services (using the Obi).
The Obi110 is configured to use the LINE interface as the primary line out.
What I noticed though is that once I inserted the Obi device, when I try to dialout a number that is to be routed over the Vonage service, there is significantly higher delay until the first ring back tone comes back.
Empirically it seems that the "extra" delay (compared to not having the obi in the chain) is around 4-5 seconds.
I also noticed that if a press "#" after the number that I dial, this extra delay is eliminated.
I searched around for the reason or a way to configure something that may reduce that delay without success.
Some of the Obi documentation (if I'm not mistaken) implies that for digits sent over the LINE interface
there is no significant delay added.
Anyone in this forum has any ideas of what may be the source of the delay? and if so, what may
be a way to eliminate it?
thanks
L.
RonR:
Quote from: lk96 on December 25, 2011, 10:37:45 am
Empirically it seems that the "extra" delay (compared to not having the obi in the chain) is around 4-5 seconds.
I also noticed that if a press "#" after the number that I dial, this extra delay is eliminated.
When you press #, the OBi bridges the PHONE Port directly to the LINE Port. You are hearing LINE Port dialtone and sending DTMF tones straight through.
When you dial normally through the OBi, the OBi first collects the entire number and processes it through DigitMaps and an OutboundCallRoute in order to determine which trunk should be used for the call. If the outbound trunk is the LINE Port, the OBi has to take the LINE Port off hook, wait 0.5 seconds to ensure dialtone is present, and then dial the number. Each digit had a 0.2 second on-time followed by a 0.2 second off-time. For an 11-digit number, that totals about 4.9 seonds.
Stewart:
@RonR,
Something doesn't jive here. I believe that the OP was describing the effect of the interdigit timeout:
Quote from: lk96 on December 25, 2011, 10:37:45 am
I also noticed that if a press "#" after the number that I dial, this extra delay is eliminated.
However, the delays you described are also present, so the total (compared with OBi out of system) would be almost ten seconds.
@lk96,
Is this a temporary setup, i.e. you would replace Vonage with a lower cost provider, once the OBi is proven? If so, the delay may be just a minor issue. OTOH, if you'll be keeping Vonage, you should probably adjust your digit maps, so that dialing # won't be necessary in most cases. For domestic calls, you can set it up to use 7 digits (local) and 11 digits (out-of-area), or to use 10 or 11 digits for all calls. If you want both 7 and 10 digit dialing, there is no way (other than pressing #) to avoid the delay on 7 digit calls.
RonR:
Quote from: Stewart on December 25, 2011, 11:45:51 am
@RonR,
Something doesn't jive here. I believe that the OP was describing the effect of the interdigit timeout:
Quote from: lk96 on December 25, 2011, 10:37:45 am
I also noticed that if a press "#" after the number that I dial, this extra delay is eliminated.
However, the delays you described are also present, so the total (compared with OBi out of system) would be almost ten seconds.
It does compute : 0.5 + 11 x (0.2 + 0.2) = 4.9 seconds
One can play with DialDelay, DialDigitOnTime, and DialDigitOffTime, but the small difference that can be achieved probably isn't worth the instability it may cause.
The default LINE Port DigitMap:
Physical Interfaces -> LINE Port -> DigitMap : (xxxxxxxS4|1xxxxxxxxxx|xx.)
contains an indefinite match rule (xx.) that will introduce an extra 2 seconds of delay (or 10 seconds when dialing a service number such as 411) that can be eliminated by pressing the # key.
I always recommend replacing the default LINE Port DigitMap with something like:
Physical Interfaces -> LINE Port -> DigitMap : ([2-9]11|[2-9]xxxxxx|1xxxxxxxxxx)
which will eliminate the extra delay if dialing is not terminated with a # key.
This assumes 7- and 11-digit dialing. If 10-digit dialing is needed, then a slightly different variation can be used.
lk96:
Quote from: Stewart on December 25, 2011, 11:45:51 am
@RonR,
Something doesn't jive here. I believe that the OP was describing the effect of the interdigit timeout:
Quote from: lk96 on December 25, 2011, 10:37:45 am
I also noticed that if a press "#" after the number that I dial, this extra delay is eliminated.
However, the delays you described are also present, so the total (compared with OBi out of system) would be almost ten seconds.
@lk96,
Is this a temporary setup, i.e. you would replace Vonage with a lower cost provider, once the OBi is proven? If so, the delay may be just a minor issue. OTOH, if you'll be keeping Vonage, you should probably adjust your digit maps, so that dialing # won't be necessary in most cases. For domestic calls, you can set it up to use 7 digits (local) and 11 digits (out-of-area), or to use 10 or 11 digits for all calls. If you want both 7 and 10 digit dialing, there is no way (other than pressing #) to avoid the delay on 7 digit calls.
This is more like the fingal config with Vonage being the "default" household line and for those in the household
that don't want to be bothered with * and # codes ;)
I do need the Obi for making low cost calls to mobiles to Europe and Asia for my own work/business,
through low cost SIP providers.
I haven't spent time familiarizing myself with the Digitmaps and route rules but will do shortly.
I should clarify that most of my calls are either 11 digit or 15 digit ones (international). So I don't have much
need/use to optimize for 7 and 10 digit numbers.
So optimizations will be needed for 11 and 15 digit numbers only.
thanks
L.
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