Keysight (formerly Agilent T&M) 4938A Network Circuit Access Test Set

The 4938A Network Circuit Access Test Set is combined with the 4937A to make up the 4937S, a complete Network Access Transmission Test Set. The 4938A provides additional network access and margin testing capabilities. It includes access to 4-wire simplexed leads, generating ringing signal, and providing access for loop current and ringing voltage measurement.