Hi Russell,

I am trying to port Asterisk over our system based on ARM 9. We have a TSI to handle voice traffic switching & DSP as a off-load engine to handle conferencing & CPT generation.

The Char Device Driver I wrote for our DSP interface, shall simply read & write data-structures to/from the DSP-queue without any knowledge of the data being written i.e. there exists no channel (FXO/FXS/ISDN etc...) level abstraction.

Well, I understand "chan_zap" communicates with its device driver through a separate node for each of the channel i.e. there exists a well defined channel level abstraction in the driver itself.

So, What do you recommend - Where should I implement this channel-level abstraction to my driver:

1) In my device driver itself by maintaining a separate queue for each channel(Kernel level), separate node & a poll implementation. --> chan_zap approach.

2) In another user-level layer which interfaces with my current naive driver on one side & on the other side interfaces with Asterisk through pipes i.e. each channel would have 2 pipes for cmd as well as event. Hence all driver specific fds (file-descriptors) in Asterisk would be actually replaced with pipe fds. --> simpler to implement & can still keep my channel driver very similar to chan_zap.

3) In the same way as chan_iax2 & chan_vpb were implemented, as discussed earlier. --> Will have to do a lot for making it as powerful as chan_zap.

Any better suggestions are welcome.

Regds. John

John Nicholas Team Lead Spectross Digital Systems Pvt. Ltd.