Voice call between android client and (JMF) PC client

Now I'm working on a voice-call project between Android and PC. I use JMF library for PC client, and normal API Android to create a voice-call between them. I use JMF because it supports RTP protocol. My problem is that the PC client can understand the packets sent from Android one, but not vice versa.

I customized code from SipDroid application and see that only two codecs are used - PCMA and PCMU. I'm not good at audio/video codec. So my question is if JMF library supports those codecs (PCMA and PCMU). I searched in Internet, and some guys say that PCMA or P开发者_如何学编程CMU is same with ULAW/ALAW, but I'm not sure that's right.

Does anyone have experience on this?

JMF supports ulaw which is called PCMU. See here.

And yes PCMU/PCMA is same as ulaw/alaw. See here.