Comtech EF Data CDM-625A Installation And Operation Manual page 156

CDM-625A Advanced Satellite Modem
Front Panel Operation
6.2.1.5.2 CONFIG: Clocks  Rx Buffer/Clock
Clk=Rx-Sat
Buffer-Size = 00016bytes(00002ms) CENTER
◄ ► arrow keys to set the Rx Clock (top line) or the Buffer-Size (bottom line).
Use the
On the top line – To set the Rx Clock, use the
ENTER. Valid settings are:
Setting
Rx-Sat
Tx-Terr
Int(SCT)
Ins(ert)
On the bottom line – To set the Buffer-Size, use the
use the arrow keys to change that digit. Press ENTER.
▲▼
Buffer Size indicates the size in bytes (and size in milliseconds) of the Plesiochronous
/ Doppler Buffer. The minimum buffer size and step size (increment) are usually the
same, and are dictated by the following rules:
If Framing is D&I or D&I++:
If D&I Type is:
E1 D&I @ 1920kbps
T1-D4
T1-ESF
E1
CONFIG: Clocks  Rx Buffer/Clock  CENTER
Selecting CENTER displays the following screen:
Press ENTER to CENTER the Buffer
otherwise, Press CLEAR
Press ENTER or CLEAR to return to the previous menu.
(Rx-Sat,TxTerr,Int(SCT),Ins)
Function
Sets the Receive buffer clock source to the satellite clock (the receive buffer is bypassed).
Note: This will fix the buffer size to minimum.
In this timing mode, data is clocked out of the receive buffer using the external transmit clock.
Data is clocked out of the buffer using the same reference that drives the modem Internal(SCT).
Available only if Rx framing is D&I and Rx interface is G.703. Sets the buffer clock to the Insert
stream.
Step size (bytes)
1024
24 x n or 3ms
48 x n or 6ms
32 x n or 4ms
arrow keys to select a parameter. Press
▲▼
◄ ►
arrow keys to select a digit, and then
Otherwise:
If data rate is:
1544 kbps (T1)
2048 kbps (E1)
6312 kbps (T2)
8448 kbps (E2)
Otherwise
6–32
MN-CDM625A
Revision 4
Step size (bytes)
1158
1024
1578
528
2, with minimum size of 16 bytes