Verizon DSL → Re: [speed/latency] hard to stay above 'dial-up' speeds - VZ dir

Even though its a dry loop line go ahead and plug a phone into the circuit when its acting up. Use a filter on that phone as if you had voice service. Pick up the phone when its acting up. You won't get a dial tone but you will either hear a recording saying you cannot make calls or something to that effect or a fast busy then silence depending on your CO and dryloop configuration. Listen for static , cross talk, or humming on the line. If any of these are present you will need to get a truck roll (check again at the demark/NID to confirm outside line issue). Another thing to try why its acting up is leave that phone off the hook and reboot modem (try to reboot while the recording is running voltage is highest in the circuit at this time). If speeds / sync come back up / margin improves you have a high open in the circuit. Leaving phone off hook maintains a standby voltage in the line and generates a sealing current temp fixing the high open.