[MT8888 can't dial. Why ?]

I use MT8888 to dial, but it can't work. I can hear DTMF tones by an audio amplifer but when I send DTMF tones to telephone line, it can't dial (can't make a call). Help me !!

[DTMF transceiver connection]

I don't think so. As fact, CM8880 is a DTMF transceiver, not like 8870 just decode DTMF. I don't know whether I should connect CM8880 to telephone line directly

[DTMF transceiver connection]

Does anyone use CM8880 to dial through phone line ? Can you help me ???? If you can, please post your circuit at least the part you connect CM8880 to telephone line ? thanks