Alexandros wrote:only help me to know if i need to send the mesage again, and to know if a user is in the hub at x time, maybe is useless i use the DCDM one now
thanks
Ask your questions using any ACK-chat-system: There are several used using different radio-protocols:
Example: "Hey billy bob! Seen my new picture of angelinas belly! Say WTF LOF if you got this message". If he doesn't answer, assume he haven't read it. ;))
Basicly such systems are rarely used in written protocols but very much used in radio-communications, like air-control, chip-control, millitary et.c....
There are email-verifications tries but most people doesn't use them. ;))
Everyone is supposed to download from the hubs, - I don´t know why, but I never do anymore.