V7122 Gateway User Guide 289CHAPTER 10: ADVANCED PSTNCONFIGURATIONGateway Clock SettingsThe gateway can either generate its own timing signals, using an internal clock, or recoverthem from one of the E1/T1 trunks. To use the internal gateway clock source configure the following parameters: TDMBusClockSource = 1 ClockMaster = 1 (for all gateway trunks) To use the recovered clock option, configure the following parameters: TDMBusClockSource = 4 ClockMaster_x = 0 (for all ‘slave’ gateway trunks connected to PBX#1) ClockMaster_x = 1 (for all ‘master’ gateway trunks connected to PBX#2)Assuming that the gateway recovers its internal clock from one of the ‘slave’ trunksconnected to PBX#1, and provides clock to PBX#2 on its ‘master’ trunks.In addition it is necessary to define from which of the ‘slave’ trunks the gateway recovers itsclock: TDMBusPSTNAutoClockEnable = 1 (the gateway automatically selects one of theconnected ‘slave’ trunks)Or TDMBusLocalReference = # (Trunk index: 0 to 7, default = 0)• To configure the TDM Bus Clock Source parameters, see Configuring SS7Tunneling.• When the gateway is used in a ‘non-span’ configuration, the internal gatewayclock must be used (as explained above).
