Analog
Phone, email, TV, internet like everywhere else.
The best kind of office phone system has multiple phone lines and voice mail messaging. Depending on the size of your business, you might even need phone conference to connect multiple lines.
You'll have to provide more information than that. What kind of phone ? What operating system is it running ?
That's an environment where you'd most likely see a halon system in use.
buyerone.com can help you decide what phone system is appropriate for your business needs. Since each business has its own unique set of needs, buyerone.com can individualize a system for you.
Blackberry has its own operating system. It is called Blackberry OS. Blackberry's can use any phone system, like Verizon, AT&T, etc. All of those services offer the same kind of phone service, but it just has a different name.
There are many questions one would ask about broadband phone system services. Someone may ask what exactly Broadband Phone System services are, what kind of charges should be expected, what are the benefits of using this type of phone system and is a contract required.
which kind of communication we have with clients in social work
One that works! iPhone - it has GPS system, map and other apps that could help you in another state.
If building a business phone system, you should include a fax machine also. You may want to include 3-way calling and also an index list to keep all your phone numbers tidy.
Non-verbal communication.
Visual communication. Body language.