Each VOIP company also offers a number of options which may or may not be of use.
A company offered part of its non-geographical telephone numbers series for IP telephones. The country codes beginning with +883 5100 area code are called INUMs and about 400 organizations have been allocated numbers in this block. Because +883 is a valid calling code, not all organizations treat them the same; however many organizations route the calls for free. An INUM is generally 15 digits long, so it is not the easiest to remember. However, in some cases it will offer you the ability to route call worldwide to a device you own, perhaps for free. You may be able to send SMS messages to an INUM. It is possible to call an INUM in the format sip:firstname.lastname@example.org.
Callcentric offers a free telephone number in NY State and it allows calls to be forwarded (or sent to a VOIP device). They also have other options, which include passing caller NAME (CNAM) that other companies may or may not pass. They also allow call treatments and the option of receiving a fax and emailing you. If you take advantage of their free telephone number in NY State, you MUST use it or it will be deleted. When signing up they tell you that. Paid numbers will not be deleted unless you ask.
VOIP.MS is another VOIP provider with similar options. A useful option is that you can (should) create sub-accounts. Each sub account has the ability for its own voicemail and extension number. These extensions each connect to an external device, PBX or perhaps are forwarded to real phone numbers (this last option would incur a cost). Extensions can call each other for free, even if devices connect to them from another country. This company also allows you to specify an outbound caller-id (spoofing), which is useful for honest people, but could be used to fool people that the call comes from someone else.
VOIP.MS also has cheap and premium routing. You might use cheap routing until you decide that you need a better connection and can change to that at any time. Premium routing costs slightly more but is a better quality. Each extension (sub-account) can be set to use either route by default. Also, a great option is that international calls can be enabled or disabled per extension and a restriction can be placed upon which locations can be called. Thus you might enable outbound calls to only the UK and block all other countries. You also can generate a call detail record for each extension.
Many VOIP services work with a service called NOMOROBO which blocks robo/automatic calls. Your srevice is configured to ring both your phone and to call NOMOROBO at the same time. NOMOROBO looks at the caller-ID and if they know it is a telemarketer or spammer, they pick up the call and hang up. So your home phone would ring once and stop. NOMOROBO is free.
As you look at VOIP companies, you should first determine what your needs are, then what would be nice to have. As each service may or may not have an account charge, you will soon see if a particular company is a good fit for you. In most cases, any of these VOIP companies will offer similar or more options at a cheaper price than a traditional telephone company. The ability to add and remove services and configure them yourself is a plus.