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Can not dial extension number

Nico Yang
Level 1
Level 1

My Company use  BE3000+SPA8800  , and our customers(use Microsoft Lync Phone ) can not dial extension number from PSTN( it is ok to connect to AA but when type extension number, there is no response). It seems that  auto-attendant device is not sensitive on DTMF signal detection(the dial pad tone) .

Why is it happen and How to solution ?

BE3000 :

PSTN Connect:SPA8800.


8 Replies 8

Cisco Employee
Cisco Employee


Do you have the extensions assigned to the keys on Autoattendant menu? So for example, if you assign the extension you are trying to reach as Key 1 on AA menu and when the AA greeting is played, if you enter 1, does that extension ring?

RFC 2833 is the DTMF type on SPA8800. There are couple of values on SPA8800 FXO Interface that you may want to change and see if that makes any difference. Those two fields are DTMF Playback Length and DTMF Playback Level.


Hi Sanjay Sinha,

I had the extensions assigned to the keys on Autoattendant menu,(press key "0",transfer to "6200",).

And SPA cannot save the changes...why? after  press the "submit all changes" button a few minutes, the system restore the changes.

I do not know what DTMF method is the Lync phone using. You may have an interop problem.

As for your other question, when you save  SPA configuration, it reboots and in the process downloads new configuration from BE3K. Hence the values you configured on SPA8800 are overwritten.

Please check if you can configure these paramters on BE3K.

But I suspect that it is an Interop problem.



You are looking at the right area. We have seen a few similar cases. For the SPA 8800 to detect DMTF it must be played for a certain duration ( I think 50 -200ms) and at a certain amplitude ( -30db to -60db) . I am not certain of the numbers in the brackets. You can achieve better results by playing around with the gain numbers. Before you start playing with the numbers, please make sure you remove the TFTP profile rule on the SPA 8800. This will prevent it from re-syncing with the BE3K. If you cant find a soution, please open a TAC case against the SPA 8800 and give me the case number. Thanks.

I also find when call from CME (SIP PHONE  "dtmf-relay sip-notify" ), it has the same problem. 不管我在BE3000或者SPA8800里做任何改动,都不能解决,但是:

After I config the CME sip phone as "dtmf-relay rtp-nte", it's works fine....

你能看的懂吧????? 我真是懒的敲ABC了,产品好就算了,不好还麻烦我脑细胞来翻译ABC给你们看~~~ 烦躁

还有: 打电话的时候老是有回音,劳资烦都烦死,是不是让我改阻抗值? 改那么多, 鬼晓得哪个合适啊!!还有,IP电话上的时间 过段时间就不对了啊啊啊啊啊 啊啊啊啊                        我还得重启啊啊啊啊啊啊

Yang Wenqin Hi, I have the same problem with the AA, could you tell me if this problem was solved by changing the parameters of DTMF and if stay was also turned, thanks.

No,The problem is not solved and I give up.

We battled with this issue for an entire year - I feel confident in stating we exhaused all our options. We replaced the SPA8800's with ISR2901+FXO, and the DTMF issue (among others) went away.

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