PMP Synchronization Solutions User Guide UGPS and CMM ConfigurationsPMP-0297 007v001 (January, 2017) 4-14UGPS and CMM ConfigurationsThe UGPS may be used as a GPS synchronization source for Cambium Networks CMM3 andCMM4 (Cluster Management Module) units. The UGPS provides GPS synchronization to the CMMunit via the CMM’s sync port. This allows any access points or backhaul masters connected to theCMM to receive sync. This configuration requires that the CMM3 or CMM4 be configured to“Slave” mode via the CMM GUI. When using the UGPS as a synchronization source for a CMM3or CMM4, a special sync cable must be used. This cable may be constructed from an RJ-11 cableusing the pin configuration in Figure 11.When using a CMM unit, the UGPS may also be used as a redundant sync source for the CMM. Ifa CMM encounters an issue with the primary, coaxial-connected GPS receiver an operator mayremotely login to the CMM and set the synchronization source to “Slave” to begin receiving syncfrom the UGPS (connected via RJ-11 cable with the pin configuration in section UGPS installationand operation).PMP 320 Systems - When using both the UGPS for timing and a CMM4 for timing in a PMP 320network (same AP site or an adjacent AP site), timing discrepancies between the UGPS andCMM4 can cause interference between the sites. To address this issue, operators may opt to useone type of timing in the network (either UGPSor CMM4). Alternatively, operators may contacttechnical support to set up remote access to troubleshoot the AP units that are exhibiting theissue. A future PMP 320 software release will address this timing issue.
