Difference between revisions of "Board Clock Management"

Latest revision as of 16:47, 30 June 2015

1.Clock Settings for Synway Board
To set the signal source of the clock for the Synway board application system, you have to consider the following factors and keep to the following principles.

1.1.For Mutual Connection between Synway Boards via CT-BUS
It is the master board that supplies the unique signal source of the master clock for the whole system.

• As long as there is one or more SHD boards in the application system, you have to choose one from the SHD boards to serve as the master board.
• If the master board is an SHD board, the signal source of the master clock must be supplied by one of the digital trunks on the master board, while the other digital trunks on the master board and those on the slave board (if available) must work in the slave clock mode.
• The clock signals supplied by the SHD boards must keep with those from PSTN; otherwise such problems as noises in call or high error rate in signaling may occur probably.

See below for related configuration items and the way to configure them.

1. If there exist SHD and other series boards in the application system, the following configuration items are necessary.
1)WhoSupplySysClock: Used to set the clock mode of the board (Master/Slave)
WhoSupplySysClock=n；0≤n≤N-1: Set the SHD board which is numbered n to be the master board, and all the others to be the slave boards (n is the set value of the configuration item TotalBoards in the configuration file ShConfig.ini. It usually is the total number of the boards).
2)PcmClockMode: Used to set the two clock modes for the digital trunks on the SHD boards.

• Line-synchronization Mode: It is often used for the connection with PBX. See below for how to configure the corresponding digital trunks.
  

PcmClockMode[0]=0; Line-synchronization (only for master board)
PcmClockMode[i]=2；i is the physical number of the digital trunk on the system board; 0＜i≤M (M is the total number of digital trunks in the system). Other digital trunks in the system should be set all to Slave Clock.

• Free-run Mode: It is used when the local end is required to supply the clock. Usually, when the SHD boards are used to simulate the PBXes to set up a test system, the Free-run mode will be selected and the configuration items of the corresponding digital trunks are as follows.
  

PcmClockMode[0]=1；Free-run (only for master board)
PcmClockMode[i]=2；
2. If there exist SHT and other series boards (exclusive of SHD) in the application system, the following configuration items are necessary.
WhoSupplySysClock=n；0≤n≤N-1: Set the board which is numbered n to be the master board, and all the others to be the slave boards. The master clock is supplied by the crystal oscillator on the master board.

1.2.For Mutual Connection between Synway Boards not via CT-BUS (with CT-BUS chip but unconnected with bus or without CT-BUS chip)
It must be a master board. As the board is unconnected via CT-BUS, even if it is set to be a slave board, it cannot acquire the clock signals from the bus. It will automatically get clock signals from the crystal oscillator to work as the master clock. If they are SHD or DTP series boards, their clock signals may differ from those coming from the PSTN of the remote PBX, which probably results in such problems as noise in call or high error rate, etc. See below for related configuration items and the way to configure them.
1.If they are SHD series boards, the following configuration items are necessary.
1）WhoSupplySysClock=N；(N is the set value of TotalBoards in the configuration file, usually being the total number of boards.
2）PcmClockMode；Used to set the two modes for the master clock.

• Line-synchronization Mode: It is often used for the connection with PBX. See below for how to configure the corresponding digital trunks.
  

PcmClockMode[0]=0；Line-synchronization (only for master board)
PcmClockMode[j]=2；j is the physical number of the digital trunk on a single board; 0＜j≤K (K is the total number of digital trunks on the board). Other digital trunks on this board should be set all to Slave Clock.

• Free-run Mode: It is used when the local end is required to supply the clock. Usually, when the SHD boards are used to simulate the PBXes to set up a call system, the Free-run mode will be selected and the configuration items of the corresponding digital trunks are as follows.

PcmClockMode[0]=1；Free-run (only for master board)
PcmClockMode[j]=2；
2.If they are DTP series boards, the following configuration items are necessary.
1) WhoSupplySysClock= N；
2) The DTP series boards supply the master clock only in the Line-synchronization mode.
The configuration items of the related digital trunks are as follows.
PcmClockMode[0]=0；Line-synchronization (only for master board)
PcmClockMode[j]=2；
3.If they are DST series or other boards (exclusive of SHD and DTP series), the following configuration items are necessary.
WhoSupplySysClock=N；The master clock is supplied by the crystal oscillator on the board itself.
1.3.For Connection of Synway and Third-party Boards via CT-BUS
If the third-party board is set to the master board, all the Synway boards should be set to the slave boards. See below for the corresponding configuration items and way to configure them.
WhoSupplySysClock= -1；
If there are SHD boards involved, PcmClockMode should be set as follows.
PcmClockMode[i]=2；i is the physical number of the digital trunk on the system board; 0＜i≤M (M is the total number of digital trunks in the system). Other digital trunks in the system should be set all to Slave Clock.

Appendix: Cautions & FAQ
In the use of the Synway boards, you have to configure the clock properly according to the above methods; otherwise, it may result in abnormalities in communications and the like. However, even if your configurations are all correct, you need pay attention to the following conditions.

1. The board is connected with CT-BUS, but the bus is disconnected or breaks down. If it is a master board, there will be nothing wrong with the board itself, however, other boards (the slave boards) in the system will suffer the clock non-synchronization trouble, which may probably result in abnormalities in communications and the like.
2. The board is set to be the master board, and the ports on it are set to work in the Line-synchronization mode. If the line breaks off or down, the ports fail to acquire clock signals from the line, the board will use the clock supplied by the crystal oscillator, which will also probably result in abnormalities in communications and the like
3. There are multiple digital trunks in the system and the default settings are used. If no CT-Bus is available, you need set WhoSupplySysClock=N (N is the total number of boards); if CT-BUS is connected, you must set a digital trunk to work in the line-synchronization mode and all the other digital trunks in the system to be slave clocks (by default, the first trunk of each digital trunk board is set working in the line-synchronization mode and only one board will be set to the master board).
4. The SHV voice-alteration boards can only be used as the slave board and can acquire the clock only from CT-BUS.
5. For more than one multi-board-multi-process system on a same machine, as different systems require different master clocks, they cannot be connected by CT-BUS; otherwise, such problems as failure in board initialization, noises on line and single-way pass may occur.