Recently set up an OS7030 with an analog trunk module in a SOHO environment, customer complained of occasional phantom single rings in the evening/night.

They happened to be sat next to a phone when this happened yesterday - the call appears to originate from an analog trunk.

I suspect that the automated line tests by the provider (BT) are incorrectly being detected as a ring.

I'm thinking of adjusting RING DET TM in TRUNK-WIDE TIMERS but have concerns that this may break caller ID detection which is preceeded by a line reversal rather than ring burst in the UK (BT have to be different to the rest of the world).

Have any UK installers come across this and got any suggestions ?

Only thing i can think of is the line good by that mean do you get noise on the line
i would try reversing the line pair in case theres a earth problem

I've seen this before on other PBX's.

Follow Gerrya's advice re the line. Also check with the line provider to see if anything else is enabled on the line - e.g braodband, Redcare, etc.

Also ,see if the line is provided via DACS - they can cause major issues with trunks on PBX kit.

I don't recall any noise on the line - I'll check that and try swapping the polarity next time I'm on site.

The line does have broadband (so no DACS), I used a replacement NTE5 faceplate with ADSL filter so the onward feed to the PBX is from the punchdown block on that.

No other phones, etc. connected to the incoming line, they have been moved to the SLT1 extension (with PFT connected and hot-dial 701 so it behaves the same with the power on or off).

Are you using AA if so you will have to get the clear disconnect timers changed to 800ms I get this problem every time I use AA with analogue lines .

After reading your post again I sure this is not your problem wired it That it only happens at night .

Not using AA or VM at the moment, so unlikely to be related to that. FWIW rather than trying to get BT to change anything (and usually get something wrong) I adjust CO SUPV TM in TRUNK-WIDE TIMERS to 90mSec which is the minimum break specified in SIN351 section 7.2.

It might be happening during the day, but the audible alert from the keysets is really short and could be missed if there is background noise.