We have someone working on a C library to use as an event socket library also. but in the meantime there is also a crude C example with no client library but just inline commands in scripts/c/socket2me this small C program demonstrates how you can use the interface to not only control the call but to also request a 2 way media stream and process the data. This application uses spandsp to implement a fax send/recv similar to asterisk's rxfax txfax only over the loopback interface.
Java ESL Client
The Java ESL Client provides an Outbound socket mode, with a simple example of how to implement land run it.