Digital voice / Fritz!box 7530 has broken my answerphone

I've been with Zen for internet and analogue phone for many years. I have a Truecall box (ie a physical box that my phone plugs into, not Truecall built into a phone or a base station). That box acts as an answer phone, interfaces with my Truecall spam database and is very simple to use requiring a single press of a physical button to hear recorded messages. Been fine for years.

A couple of months ago I moved to digital voice with Zen and they gave me a new Fritz!box 7530 to be able to use voip. My internal phone wiring is now plugged into the Fritz!box instead of the BT master socket and I can make and receive calls with no issues.

However, since moving to digital voice the answer phone in the Truecall box is no longer receiving the line disconnect signal when the calling number hangs up (first party disconnect). I understand that this should cause a number unobtainable tone to be sent that (previously) was detected by the Truecall box which ended the answer phone recording.

Now, if someone hangs up after leaving a message the answer phone continues to record a series of tones for several minutes after the message ends. If the caller doesn't leave a message but just hangs up then I still get several minutes worth of the tone recorded as a 'message' on the answer phone.

I've spoken to Zen who first of all said I should use the answer phone in the fritzbox, which I don't wish to do as I can't see the point of having an app on my mobile phone to listen to messages sent to my landline, nor of getting emails sent and me having to check my emails. I like pressing a single, physical button in my kitchen. Now they are saying it’s a fault with my Truecall box, which I doubt as it has worked fine until they changed me to digital voice.

This seems to be an issue with some BT phones with built in answer phones as well after moving to voip and the answer always seems to be the equipment in the exchange not sending the correct signals.

Has anyone else experienced a similar issue with Zen? Any ideas how to get this fixed or how to get Zen to even check the exchange?

The analogue tones will only come from the Fritz!box now rather than the exchange, since the router has to generate the various tones locally for the analogue port in place of what would have come down on the voice pair.

The tones used for different states (dialling tone, engaged, unobtainable, call ended, call waiting, off-hook alert/timeout and such) are not universally the same worldwide, different countries have their own conventions.

It is likely any change would need to be made in the Fritz!box firmware - and I don't know if it has any internal settings relating to regional variations for the analogue port though.

I have a different setup - testing VOIP before moving my landline later

BT (no BT Digital voice) with a Grandstream HT801 ATA providing VOIP capability (A&A) and a BT Decor 2600 Truecall phone.

I call the VOIP number and let the answerphone kick in, I leave a message and terminate the call, I hear 3x busy tone before the 2600 ends the call. On playback, the recorded message has 1x busy tone at the end of the recording.

I will try to test using an analogue answer phone without Truecall tomorrow to see if it behaves the same. I know I could turn Truecall off on the 2600 but using a device without Truecall will tell me if Truecall is the issue or whether it is related to the answerphone functionality

Just repeated with a Panasonic analogue answer phone / DECT setup

When the caller I terminated the incoming call I heard 6x busy tones on the base unit. Answer screening was set on. On playback the message had 3x busy tones at the end of the message.

Busy tone is beep, beep, beep, beep - around 3 beeps per second.

Looks like it is the answerphone capability and not Truecall which is causing the issue.

I am not aware that old technology (analogue) equipment needs to be 100% compatible with newer digital VOIP technology.

All the tones and things are usually set in the ATA, and out of the box they might be configured for the USA region. For a Grandstream ATA the UK settings are http://web.archive.org/web/20221002044654/https://ww...

(link from the AAISP wiki)

Hi jpm, yes, I have configured the ATA for UK settings.

After doing another test - called my VOIP number from my mobile with the ATA connected to a BT Viscount (we're going back some years now!) telephone. I answered and then ended the call on my mobile. The Viscount gave an engaged type tone after the call ended for around 60 seconds. After which it appeared to give a handset off hook tone (rapid beeping).

Looks like Truecall / Answerphone is not the issue.

Could it be a mismatch between mobile and VOIP? Perhaps I have setting wrong in the ATA? I will check later.

I think I noticed the same when I was testing my Dad's BT DV a few months ago, but cannot be sure.

It does look like "line disconnect" is not being processed correctly. Strange this hasn't been raised before. I will check my settings - although OP (bbuser150) has probably just used the standard Zen / 7530 settings.

Edited by BarkingMad (Thu 20-Jul-23 08:56:24)

I'll go quiet for a while after this. I may have hijacked OP thread but just providing more info. Sorry

Just tried another combination - N300A / C530 on Sipgate. When mobile terminates the call, the C530 gives 3 busy beeps before returning to idle state.

Summary of my testing of calls from mobile to VOIP numbers with mobile terminating the call - what is heard at receiving phone:

- GS HT801ATA + Decor 2600 Truecall with A&A. 3x busy tone heard and 1x busy tone on the recording
- As above with Panasonic Answerphone/DECT. 6x busy tone heard and 3x busy tone on the recording
- As above with BT Viscount phone (basic phone). 60 seconds of busy tone before number off hook tone
- N300IP / C530 with Sipgate: 3x busy beeps before returning to idle.

@bbuser150 Have you had your firmware updated on the Truecall box? Might be worth a go

@ BarkingMad
I haven't made any particular changes to the Fritz!box settings, except to turn off the built in answerphone. My recordings are similar to yours, About 60s of slow beeps followed by a short burst of fast ones, maybe corresponding to recording to the engaged/ off hook tones.

Zen got back to me and said that the Truecall FAQs say it is not 'recommended' to use truecall with voip and washed their hands of the issue. The FAQs do indeed say that but don't say why. However the set up instructions say that it can be used with 'some' voip and to look on page 16 for details, but page 16 doesn't mention voip.

I don't know what truecall uses to detect first party disconnect in the UK. If its the number unobtainable tone or the engaged tone then it looks like it is still receiving it from the Fritz!box but is now recording it instead. However, if it was looking for a voltage drop on the line or something like that then it could be that the Fritz!box is not providing this.

I've contacted Trucall and await their reply

Just to add my two pence worth. I have had a Fritz!box VOIP connection for over 5 years. I have never seen the need for anything other than the Fritz!box.

Nuisance calls are directed to a dedicated answering box. In my experience, they never leave a message.