Hey Jeff, Seems like we discussed this a while ago, but I can't find the thread

It varies so much from state to state, its hard to say, but many have rules that say you can be referred to as an engineer internally, within your company as a title, but you can't have cards or signature blocks that say "engineer".  Some states have protected disciplines that have an exam and license, but you can be a "Design Engineer" or "Sales Engineer" or "Installation Engineer" since those jobs/disciplines don't have an exam.

From Wikipedia:

United States
In the United States, most states prohibit unlicensed persons from calling themselves an "engineer" or indicating branches or specialities not covered by the licensing acts.[citation needed]

The title "engineer" is legally protected in many states, meaning that it is unlawful to use it to offer engineering services to the public unless permission, certification, or other official endorsement is specifically granted by that state, through a professional engineering license, an "industrial exemption", or certain other non-engineering titles such as "operating engineer".[citation needed] Employees of state or federal agencies may also call themselves engineers if that term appears in their official job title. The IEEE's formal position on this is as follows: "The title, engineer, and its derivatives should be reserved for those individuals whose education and experience qualify them to practice in a manner that protects public safety. Strict use of the title serves the interest of both the IEEE-USA and the public by providing a recognized designation by which those qualified to practice engineering may be identified."[citation needed] It is generally a requirement in the United States to have at least a Bachelor of Science degree in an engineering discipline or related applied science to be considered an engineer and practice as such.[citation needed]

A business generally cannot offer engineering services to the public or have a name that implies that it does so unless it employs at least one professional engineer.

Due to industrial exemption many non-professional engineers are titled as engineers. Examples are production engineer, test engineer, integration engineer, network engineer, project engineer, systems engineer and sales engineer.

This is seen in engineering job advertisements on line and in news papers, most of the advertisements and employers don't require licensing due to the industrial exemption.[citation needed]

In the United States, use of the title professional engineer is restricted to those holding a professional engineer's license. These people have the right to add the letters PE after their names on resumes, business cards and other communication. However, each state has its own licensing procedure, and the license is valid only in the state that granted it.[citation needed]

Other uses of the term engineer are legally controlled and protected to varying degrees, dependent on the state and the enforcement of its engineering certification board. The term is frequently applied to fields where practitioners may have no engineering background, or the work has no basis in the physical engineering disciplines; for example sanitation engineer. However, in many jurisdictions, the usage of this term is limited to internal use by a company, rather than in a professional or marketing aspect, if said company is not licensed to perform engineering work. This is because what is legally recognized as engineering work (and thus requiring licensure to be practiced) is held to strict criminal liability.[36]

With regard to the term "software engineer", many states, such as Texas and Florida, have license requirements for such a title that are in line with the requirements for more traditional engineering fields.

From TX legislature:
Sec. 1001.004.  LEGISLATIVE PURPOSE AND INTENT;  LIBERAL CONSTRUCTION OF CHAPTER.  (a)  The legislature recognizes the vital impact that the rapid advance of knowledge of the mathematical, physical, and engineering sciences as applied in the practice of engineering has on the lives, property, economy, and security of state residents and the national defense.
(b)  The purpose of this chapter is to:
(1)  protect the public health, safety, and welfare;
(2)  enable the state and the public to identify persons authorized to practice engineering in this state;  and
(3)  fix responsibility for work done or services or acts performed in the practice of engineering.
(c)  The legislature intends that:
(1)  the privilege of practicing engineering be entrusted only to a person licensed and practicing under this chapter;
(2)  only a person licensed under this chapter may:
(A)  engage in the practice of engineering;
(B)  be represented in any way as any kind of "engineer";  or
(C)  make any professional use of the term "engineer";  and
(3)  this chapter be strictly complied with and enforced.
(d)  This chapter shall be liberally construed to carry out the intent of the legislature.
(e)  This chapter does not:
(1)  prevent a person from identifying the person in the name and trade of any engineers' labor organization with which the person is affiliated;
(2)  prohibit or otherwise restrict a person from giving testimony or preparing an exhibit or document for the sole purpose of being placed in evidence before an administrative or judicial tribunal, subject to the board's disciplinary powers under Subchapter J regarding negligence, incompetency, or misconduct in the practice of engineering;
(3)  repeal or amend a law affecting or regulating a licensed state land surveyor;  or
(4)  affect or prevent the practice of any other legally recognized profession by a member of the profession who is licensed by the state or under the state's authority.