B800P echo + DTMF problem

We have a B800P card running with Asterisk 1.6.0.6 + MISDN 1.9.1.

We have a couple of problems with the setup:

1. echo. The people inside the office can hear a delayed version of their own voice (customers outside the office cannot hear this, but it is distracting for the staff). Dropping the tx + rx gain hasn't helped.
2. Outgoing DTMF doesn't work properly. Automated systems don't recognise the keypresses. I used one of the phones to call my mobile to test it, and pressed some phone keys, the tone was just a short 'blip' not a long tone as I expected.
3. Lines do not get re-enabled if for example a cable was unplugged, then reconnected.

Any ideas?
Thanks!

1. what kind of device you are using in office? ISDN phone or SIP phone or SIP softphone?
all kind of such device have similer issue?
2. Asterisk will re-generate DTMF, that's why some time Automated systems can not recognize your key, but some version of asterisk seems have better performance on this issue. for example, 1.4.8 work well with it, so my suggestion is try another asterisk + mISDN
3.do not know what you mean?

hello,
I do not test the combination of asterisk-1.6 and mISDN-1.1.9. have you patch mISDN-1.1.9 for B800P?
i suggest you using the asterisk-1.4.20 and mISDN-1.1.7 patched. get the patch from:
www.openvox.com.cn/downloadsFile/b800P_patch_1_1_7
regarding the your problem, please :
1) open the echo cancel.
2) dtmf must enabled. what is you terminal? SIP or IAX? please check the SIP dtmfmode.
3) it can be reconnected with mISDN-1.1.8 and 1.1.7, but i am not sure what the problem is with 1.1.9 .
regards!
James.zhu

Thanks very much for your suggestions, I will try those as soon as possible and report back.

in number 3, I mean that if I unplug a cable from the card, then run "misdn show stacks" the line will never come back UP. It will always show as DOWN.