CDM-600 Satellite Modem Revision 7
Front Panel Operation MN/CDM600.IOM
6–20
CONFIG:CLOCKS: RX BUFFER/CLOCK
Use the [] [] arrow keys to select one of the three parameters on the screen to edit.
Edit the RX clock options using the [] [] arrow keys, then press ENTER
RX-SAT Sets the Receive buffer clock source to the satellite clock (The receive buffer will
be bypassed.) Note: This will fix the buffer size to minimum.
TX-TERR In this timing mode, data is clocked out of the receive buffer using the external
transmit clock.
EXT-CLK In this timing mode, data is clocked out of the receive buffer using an External
clock.
INS Sets the buffer clock to the Insert stream (INSERT mode only).
Buffer-Size indicates the size, in bytes, of the Plesiochronous/Doppler Buffer. In
parentheses after this, the size in milliseconds is shown. Edit each digit of the buffer size
using the [] [] arrow keys. Press ENTER.
Note: When the RX data rate is set to one of the four G.703 rates, the minimum buffer
size and step size are limited to the value shown in the table below. In addition, Insert
Framing follows the same rule, regardless of n x 64 data rate, depending upon whether
the Insert Type is T1 or E1. If none of these cases is true, the minimum buffer size is
16 bytes with a step size of 2 bytes.
RX Data Rate Buffer Step Size
1544 kbps (T1) or open network D&I at T1 1158 bytes or 3 milliseconds for D4
(6 milliseconds for ESF)
2048 kbps (E1) or open network D&I at E1 1024 bytes or 4 milliseconds
D&I++ at n = 1, 3 or 5 720 bytes
D&I++ at n = 2, 6 10 or 15 1440 bytes
D&I++ at n = 9 2160 bytes
D&I++ at n = 4, 12 or 20 2880 bytes
D&I++ at n = 18 4320 bytes
D&I++ at n = 7 or 21 5040 bytes
D&I++ at n = 8 or 24 5760 bytes
D&I++ at n = 11 7920 bytes
D&I++ at n = 13 9360 bytes
D&I++ at n = 14 10080 bytes
D&I++ at n = 16 11520 bytes
D&I++ at n = 17 12240 bytes
D&I++ at n = 19 13680 bytes
D&I++ at n = 22 15840 bytes
D&I++ at n = 23 16560 bytes
6312 kbps (T2) 1578 bytes or 2 milliseconds
8448 kbps (E2) 528 bytes or 0.5 millis econds

CLK= RX-SAT (RX-SAT,TX-TERR,EXT-CLK,INS)

BUFFER-SIZE = 00016bytes(00002ms) CENTER