| A small survey
Most PBXs run with a Stratum 4 Clock. Since you have only one reference, and that too when it slips, it is definitely less reliable to be on a Free Run Mode as then the PBX would start running on a Stratum 4 Clock(Own Clock) , whereas when you take a clock from the T1 it would be a Stratum 3 clock which is more reliable.
Try and get one more source or else in free run mode, you could have some slippages/crcs while TX/RX. |