An optical adapter block assembly comprising: (a) a first adapter block (710, 710A) having a front, a rear, a top, a bottom, a first side, and a second side, the first adapter block (710, 710A) defining a plurality of ports, the first adapter block (710, 710A) defining a plurality of apertures at the top, the apertures being associated with the ports; (b) a plurality of contact assemblies disposed in the apertures of the first adapter block (710, 710A) so that portions of each contact assembly extend into an interior of the first adapter block (710, 710A); (c) a circuit board arrangement having a first side and a second side, the first side including circuit board components and the second side being configured to seat on the first adapter block (710, 710A), the second side also being configured to electrically connect to the contact assemblies disposed in the apertures of the first adapter block (710, 710A), wherein the circuit board arrangement includes an electrical connector having pins that extend outwardly from the second side of the circuit board arrangement; (d) a cover configured to seat on the first side of the circuit board arrangement, the cover being attached to the first adapter block (710, 710A) so that the circuit board arrangement is held to the first adapter block (710, 710A) by the cover; and (e) a second adapter block (710, 710B) having a front, a rear, a top, a bottom, a first side, and a second side, the second adapter block (710, 710B) defining a plurality of ports, the second adapter block (710, 710B) defining a plurality of apertures at the top, the apertures being associated with the ports; and; (f) a joining member configured to couple together the first adapter block (710, 710A) and the second adapter block (710, 710B) as a unit; characterized in that: the first adapter block (710, 710A) includes a first engagement member that extends outwardly from the first side of the first adapter block (710, 710A); the second adapter block (710, 710B) includes a second engagement member that extends outwardly from the second side of the second adapter block (710, 710B); and the joining member includes a body defining one or more interior cavities that are sized to receive the engagement members of the first and second adapter blocks (710, 710A, 710B), wherein the joining member defines at least one shroud through which the pins of the electrical connector extend. (a) a first adapter block (710, 710A) having a front, a rear, a top, a bottom, a first side, and a second side, the first adapter block (710, 710A) defining a plurality of ports, the first adapter block (710, 710A) defining a plurality of apertures at the top, the apertures being associated with the ports; (b) a plurality of contact assemblies disposed in the apertures of the first adapter block (710, 710A) so that portions of each contact assembly extend into an interior of the first adapter block (710, 710A); (c) a circuit board arrangement having a first side and a second side, the first side including circuit board components and the second side being configured to seat on the first adapter block (710, 710A), the second side also being configured to electrically connect to the contact assemblies disposed in the apertures of the first adapter block (710, 710A), wherein the circuit board arrangement includes an electrical connector having pins that extend outwardly from the second side of the circuit board arrangement; (d) a cover configured to seat on the first side of the circuit board arrangement, the cover being attached to the first adapter block (710, 710A) so that the circuit board arrangement is held to the first adapter block (710, 710A) by the cover; and (e) a second adapter block (710, 710B) having a front, a rear, a top, a bottom, a first side, and a second side, the second adapter block (710, 710B) defining a plurality of ports, the second adapter block (710, 710B) defining a plurality of apertures at the top, the apertures being associated with the ports; and; (f) a joining member configured to couple together the first adapter block (710, 710A) and the second adapter block (710, 710B) as a unit; the first adapter block (710, 710A) includes a first engagement member that extends outwardly from the first side of the first adapter block (710, 710A); the second adapter block (710, 710B) includes a second engagement member that extends outwardly from the second side of the second adapter block (710, 710B); and the joining member includes a body defining one or more interior cavities that are sized to receive the engagement members of the first and second adapter blocks (710, 710A, 710B), wherein the joining member defines at least one shroud through which the pins of the electrical connector extend.