namic time error (dTE), relative time error, noise tolerance, and noise transfer. Transient response requirements are for further study and there is no holdover capability sup- ported in a transparent clock. Appendix I, "Traffic load test patterns" (describes some guidelines for testing transparent clocks) Appendix III, "Performance estimation for cascaded media converters acting as T-TCs" This recommendation defines the noise generation performance of T-TC clocks into three classes, Classes A, B, and C (in order of increasing performance). The requirements for these three classes mirror those from the T-BC and T-TSC cases. Note that the recommendation focuses on syntonized T-TC clocks, meaning that some physical method (commonly SyncE) is used for frequency synchronization of the T-TC clocks. Therefore, it also requires "physical frequency support" and applies only to transparent clocks running in end-to- end transport clock mode (see the section "End-to-End Transparent Clocks" in Chapter 7). It also assumes that the deployment meets the end-to-end network limits for full timing support (from G.8271.1) and that it uses the G.8275.1 PTP telecom profile. A new version of G.8273.3 was consented at the October 2020 plenary. Link to recommendation: https://handle.itu.int/11.1002/1000/14508 G.8273.4: Timing Characteristics of Telecom Boundary Clocks and Telecom Time Slave Clocks for Use with Partial Timing Support from the Network ITU-T G.8273.4 specifies the minimum requirements for synchronization clocks used in a time and phase synchronization network operating in either APTS or PTS architectures. From the scope of the recommendation: This Recommendation allows for proper network operation for phase/time synchronization distribution when a network equipment embedding an APTS or a PTS clock is timed from another telecom boundary clock (T-BC) or a telecom grandmaster (T-GM). This Recom- mendation specifies the minimum requirements for APTS and PTS clocks in network ele- ments (NEs). These requirements apply under the