UK regionalisation, tones etc.

[David_W]

Following the questions I've asked in the forums, and the delivery of my SPA-3000 today, I've been working out the various tones etc. as used in the UK.

Some of this information is right or nearly right in the wizards now - some is missing. I don't think anyone has produced what I believe to be a comprehensive and correct set of PSTN settings for the SPA-3000.

If anyone wants to check this information (and I'd be glad if they did - I'm a novice at configuring Sipura boxes and I may well have got some of my tones, cadences and frequencies wrong), the BT SINs can be got from http://www.sinet.bt.com


Regional

following BT SIN 350 issue 1.2

Dial tone: (current wizard levels wrong - 440Hz should be 3dB down)
350@-19,440@-22;10(*/0/1+2)

Ring back: (current wizard is correct)
400@-20,450@-20;*(.4/.2/1+2,.4/2/1+2)

Busy tone: (current wizard has the cadence slightly wrong)
400@-20;10(.375/.375/1)

Reorder tone:
400@-20;10(*/0/1)

SIT 1 tone:
950@-16,1400@-16,1800@-16;20(.330/0/1,.330/0/2,.330/0/3,0/1/0)

MWI dial tone:
350@-19,440@-22;10(.75/.75/1+2)

CWT1 cadence:
30(.1/2)

CWT2 cadence:
30(.25/.25,.25/.25,.25/5)

CWT frequency:
400@-10


following BT SIN 351 issue 4.2

Ring 1 cadence:
60(.4/.2,.4/2)

Ring 2 cadence (used for BT Call Sign):
60(1/2)

Ring 3 cadence (used for BT Ring Back):
60(.25/.25,.25/.25,.25/1.75)

Ring 4 cadence:
60(.4/.8)

Ring 5 cadence:
60(2/4)


Regional Settings - Miscellaneous

Time Zone: GMT
FXS Port Impedance: 370+620||310nF
Caller ID Method: ETSI FSK With PR(UK)


PSTN line settings for SPA-3000

as per BT SIN 350 issue 1.2

PSTN Disconnect Detection

Detect CPC: yes
Detect Polarity Reversal: no (I think yes may lead to nuisance disconnects, though I forget exactly how Caller ID on Call Waiting is signalled and I haven't yet had time to re-read the relevant BT SINs)
Detect PSTN Long Silence: yes
PSTN Long Silence Duration: 30
Min CPC Duration: 0.085 (actually that's a bit conservative - the spec is 0.09)
Detect Disconnect Tone: yes
Disconnect Tone: 400@-30;20(*/0/1)


International Control

FXO Port Impedance: 370+620||310nF
Tip/Ring Voltage Adjust: 3.5V (default, seems to work)
Operational Loop Current Min: 10mA (default, seems to work)
On-Hook Speed: 3ms (ETSI) (seems right - UK is ETSI)
Current Limiting Enable: yes (seems right - UK should be approving to CTR21)
Line-In-Use Voltage: 30 (default, seems to work)
Ring Frequency Min: 10 (default, seems to work)
Ring Frequency Max: 100 (default, seems to work)
Ring Validation Time: 256ms
Ring Indication Delay: 0
Ring Timeout: 128ms
Ring Threshold: 13.5-16.5 Vrms (default, seems to work)
Ringer Impedance: High (Normal) (default, seems to work).


With these settings and 2.0.13(GWg) firmware on my SPA-3000, incoming BT CDS (UK) CLID is recognised from a BT System X exchange.


Has anyone got their hands on the UK specification for timed-break recall (hook flash)? The defaults in the SPA-3000 are very US-centric. 0.9s hook flash is way longer than allowed in the UK.


I hope this is useful.



David

(Edit to correct 0.9s hook flash - I had incorrectly written 0.9ms)

[mberlant]

David,

That information is terrific. I would agree with you that 0.9s hook flash is too long. Most switches are happiest between 450 and 500 ms, with 1500ms as the typical debounce disconnect interval. I'll see if I can confirm what UK like best.

Michael

[bert1e]

Thanks for all these settings. I have a problem with my pstn line giving me random calls a bit like the sporadic thread elsewhere on the forum. Anyhow as I have my sipura connected to PSTN in the UK I will give your settings a go and let you know if I have any problems. I just hope your settings happen to fix my sporadic calls. Thanks again

[David_W]

It appears that most of the phones that offer time break recall have a default interval of around 100ms. Does .08 to .2 seconds seem reasonable?

bert1e's problem sounds, to me, like the VMWI ring splash interval not being set to 0, as has already been suggested in the other thread.



David

[Kristopher83]

Great Bit of research, and will come in very handy especially for us sipura users wanting to make our ATA's sound more like normal phones. I would suggest however that the hook flash is set to 0.06 secs. We experimented with a couple of dect phones at work and it made all the difference. From a quality perspective the FXO Port Impedance value of 370+620||310nF makes a real differnce to the tonal qualities.

[mberlant]

There is ergonomic argument that goes into the decisionmaking for whether to set the Dial Tone to UK local or US (or some other) value.

On the one hand, it is very comforting to hear the familiar BT Call Progress Tones. On the other hand, if you are using an SPA-3000 and its PSTN Line is connected to a real BT/NTI trunk you may prefer to have a "different" Dial Tone so that you can instantaneously distinguish when your VoIP service is down and your SPA-3000 has gone into failsafe mode.

If you pick up the phone and hear a US Dial Tone you are using the VoIP service. If you pick up the phone and hear a UK Dial Tone you are in failsafe mode, and may not want to make that international call just now.

All in all, it is personal preference (mostly, your wife's) that will drive this decision.

[craig]

mberlant,

It's interesting that you mention this. I made the changes above and was a bit surprised (I shouldn't have been, but I was) when calling my parents in the US and hearing a UK ring. I hung up, thinking I'd got it wrong and dialled again. Needless to say, I am going to change it back to a US ring!

Craig

[mberlant]

Actually, that is proper behaviour with today's technology. With the internationalisation of SS7 over the last 20 years, signalling is almost entirely out-of-band now.

In today's world, when you make a telephone call you don't actually get a voice channel until a split second after the destination party picks up the phone. Your switch sends a call request on a control channel down the line to the destination switch. The destination switch checks the target number for availability to take the call and returns the appropriate call control packet to your switch, either "Ringing" or "Busy" or "Unavailable", etc. Your local switch then generates the appropriate Call Progress Tone and puts it in your ear. Gone are the days when you actually heard the ringback signal or busy signal from the distant end.

That is why, no matter where in the world you ring nowadays it sounds like you are ringing your next door neighbour. If you decide to change all of your Call Progress Tones to US standard and call somewhere in the UK (or Mexico or Japan or Switzerland) you will hear US Call Progress Tones.

[David_W]

To add some further information to the above:

Regional tab (for all of these settings)

Hook Flash Timer Min: .06
Hook Flash Timer Max: .2

(as discussed above, this is about right - most UK phones with a 'recall' button flash for around 100ms).


CPC duration: .1

(that's the CPC the SPA generates on the FXS side, and is in the middle of the BT specification for what they call a K-break - it will help if whatever you've got on the FXS port looks for CPC, such as a PABX. The Sipura defaults don't have a K-break on the FXS side).


Ring frequency: 25
Ring voltage: 70

(these are the UK specifications and the Sipura defaults - the default ring frequency of 25Hz is wrong for US phones, which want 20Hz, but right for UK phones. Ring voltage is 50V rms on a UK line - the Sipura docs indicate that such a low setting is not allowed, so I'm assuming it's not rms and have set this to 70V, which is approximately 50V rms).


I take the point about not knowing whether your SPA-3000 is in pass through mode or not if you have a BT dial tone. My preferred way ahead is to introduce a slight stutter in the dial tone and use 350@-19,440@-22;10(.9/.1/1+2) - I can hear the difference between that, a BT dial tone (continuous) and a MWI dial tone (.5/.5) I have BT Call Barring and BT Option 3 (at least for now) on the PSTN line, so sending UK inland calls over the PSTN line is no disaster and international and premium rate are barred anyway.

The aim of the information given above was to replicate exactly BT tones etc. - especially for people using SPAs other than the SPA-3000 who want a UK 'feel' to the VoIP. If you wish to deviate from any of this, feel free. The aim of starting this thread was to get all the information on UK tones, FXS and, for the SPA-3000, FXO settings in one place.

Is there any chance of the Voxilla localisation wizard being updated with all this? Options of UK with the dial tone string as "UK", "US" and "UK with slight stutter" may make sense.



David

[ijones]

Hello


Thanks very much for researching this - I have been looking for an authorative source for BT standards/settings, and you've saved me the trouble.

I have applied your recommendations over those set by the wizard on this site, however although things are now better, they are not yet 100%. My biggest issue is that incoming PSTN calls are dropped when I try to answer them, and I get dial-tone instead (PS: Using a Panasonic DECT phone if that is relevant).

I'd appreciate any suggestions as to what settings to tweak to resolve this.


Cheers