Manufacturers
- Saba
- Saime
- Samar
- Samsung
- Sangean
- Sansui
- Sanwa
- Sanyo
- Satorius
- SBE Sideband Engineers Inc.
- Schaffner
- Schaub-Lorenz
- Schiller Medical SA
- Schlumberger
- Schomandl
- Scott
- Seca
- Seco Manufacturing Company
- Seiko I Infotech Inc.
- Semcor
- Sencore
- Sennheiser Electronic
- Sequential Circuits
- Sharp
- Sherwood
- Shure
- SIARE HOSPITAL SUPPLIES S.r.l.
- Siel
- Siemens
- Sigma Corporation
- Silver Marshall Inc.
- Simpson
- SIMS Graseby
- Sinclair
- Singer
- Singer Instrumentation
- Sinudyne
- Skanti
- Skuttle
- Slade Radio PTY LTD
- SLE
- Smiths Radiomobile
- SOCIETE FRANÇAISE RADIO - ÉLECTRIQUE
- Solar Manufacturing Corporation
- Solartron
- Sommerkamp
- SonoSite, Inc.
- Sony
- Sony Ericsson
- Sorensen Company
- SP Radiotechnika Wroclaw
- Spectracom
- Spectronics
- Spilsbury Communications Ltd.
- Spirent Communications
- Spirent Communications, Inc.
- Spraque Electric Company
- SRS Stanford Research Systems
- Stancor Standard Transformer Corporation
- Standard Communications
- Standard Radio & Telefon AB
- Statron
- Stearns Magnetics
- Stoelting
- Studer
- Subaru
- Sun Microsystems
- Superior Instruments Co,
- Supreme Instruments Corporation
- Swan Electronics Corp.
- Sylvania Electric Products
- Symetrix
- Systron Donner
