Telecommunications Engineering
| Digital Switching & Related Interfaces | Acceptance Testing and System Validation |
| Plain Old Telephone Service (POTS) | Twisted Pair & Fiber Optic Cable |
| ISDN Basic & Primary Rate Interface (BRI & PRI) | End office and Tandem (Transit) Switching Systems |
| Switched 56 (Type I and III) | Transmission & Multiplex Systems, DS1, DS3, SONET |
| DS1 Rate Digital Trunk Interface | Support Systems (see below) |
| Caller Number & Caller Name Delivery | National Electrical Code® (NEC® ) |
| Digital Subscriber Line (xDSL) | National Electrical Safety Code (NESC) |
| Signaling System No. 7 link interfaces and protocols | Signaling System No. 7 messaging including ISUP, SCCP and TCAP including 800NS, IS41A, CLASS (CNAM and CND) |
| Access networks, access nodes and digital loop carrier (DLC) | Access networks, access nodes and digital loop carrier (DLC) |
| GR303 Integrated DLC Interfaces | Communications Assistance Law Enforcement Act (CALEA) |
| Voice Over IP (VoIP) and Voice of ATM (VoATM) | Voice Quality Testing for packet networks |
| Support Systems | Transmission & Related Interfaces |
| IP telephony infrastructure | xDSL Local Loop Access |
| Building Integrated Timing Supply (BITS) including GPS | Fiber Optic including SONET BLSR and UPSR |
| DC and AC Power Systems (commercial and standby) | Digital Loop Carrier (Integrated and Universal DLC) and Full Services Access Networks (FSAN) |
| Earth Grounding Systems | Repeatered T1-Carrier |
| Cable & Equipment Electrical Protection | High Bit-Rate Digital Subscriber Line (HDSL, HDSL2 and HDSL4), Symmetric HDSL (SHDSL) and ISDN Digital Subscriber Line (DSL) |
| Underground Raceway, Duct & Conduit Systems | Wireless Local Loop (WLL) for voice and internet access |
| Alarm Systems | Digital Microwave Radio (fixed wireless) including unlicensed spread spectrum radio |
| Equipment & Cable Structural Support Systems | Subrate Dedicated Digital Service (DDS) loops to 64 kb/s |
| Buried, Underground and Aerial Pole Line Systems | Fractional T1 |
| Operational Support Systems (OSS) | Channel Banks (Primary Multiplexers), M13 Multiplexers & Digital Cross-Connect Systems (DACS and DCS) |
| FCC Licensing | Wide Area Network (WAN) including IP |
| VHF, UHF & Microwave Point-to-Point | Basic Exchange Telephone Radio Service (BETRS) and Rural Radio Service |
