UDP Socket

[Tobias Reithmaier]

Hello,
I have a question about emacs-lisp programming.There is a lack of documentation 
for socket programming.
I want to create an echo-Application.For Example:

(make-network-process :name "udp-socket1" :remote '[127 0 0 1 1500] :type 
'datagram :filter 'print-it)(process-send-string "udp-socket1" "hello").
...now hopefully this sends an udp-datagram...How can i receive one?
I guess, because where is no receive-function, this network-process receives 
datagrams automatically.But how can i send datagrams to over an udp-connection 
to this process.Not (process-send), but over udp with another elisp-program?

regards
Tobias