Calling Asterisk SIP phone not working

I have Openfire and Spark working for IM with Asterisk-IM. However, when I call an Asterisk SIP phoen via Spark, the other end can answer but we cannot communicate to each other. I do not know where to turn in the configuration. Does anybody know how to fix this issue?

To me that sounds more like a problem with your Asterisk configuration than with Asterisk-IM as Asterisk-IM is only involved with call signalling and not with the media path. Make sure that both participants can hear each other when dialing directly, i.e. without Asterisk-IM.

Asterisk is working fine with other softphones, like x-lite and sjphone. I think the issue is that there is no configuration for which headset, speakers, mic, to use. The others (like x-lite) allow me to choose which audio devices to use and I use my Logitech USB headset as both my default Windows device and my x-lite device. When using Spark, the other person answers with Spark, they can hear my voice through their speaker (not through the headset) but I cannot hear them. Ah, maybe I need to have him set his computer to have his headset as the default Windows device (ding, ding, ding)!!