Knowledge of space weather effects on communications systems continues to improve, though additional research is needed. Effects are defined in the Space Weather Phase 1 Benchmarks report from the Space Weather Operations, Research, and Mitigation (SWORM) Subcommittee of the National Science and Technology Council and include: induced geo-electric fields, ionizing radiation, ionospheric disturbances, solar radio bursts, and upper atmospheric expansion. These effects, which arise primarily from solar flare radio blackouts, solar radiation storms, and geomagnetic storms, will be mapped against technologies and environments to highlight vulnerabilities, describe risks, and identify possible mitigation strategies. Gaps in current knowledge will be discussed where additional research would provide opportunity for improved technologies and practices to further mitigate space weather effects.