Comtech EF Data CDM-600/600L - Manual (Page 96)

CDM-600/600L Open Network Satellite Modem Revision 3
Front Panel Operation MN/CDM600L.IOM
5–20
5.4.5.2 CONFIG: CLOCKS
Æ RX-BUFFER/CLOCK
CLK= RX-SAT (RX-SAT,TX-TERR,EXT-CLK,INS)
BUFFER-SIZE = 00016bytes(00002ms) CENTER
Use the [ ←][→] arrows keys to select for editing the Rx Clock (top line) or the Buffer-Size
(bottom line).
CONFIG: CLOCKS Æ RX-BUFFER/CLOCK Æ RX CLOCK
On the top line, select Rx-Sat, Tx-Terr, Ext-Clk, or Ins using the [ ↑][↓] arrow keys. Note the
following:
RX-SAT
Rx Satellite Clock: 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
External Transmit Clock: In this timing mode, data is clocked out of the
receive buffer using the external transmit clock.
EXT-CLK
External Clock: Data is clocked out of the buffer using the same reference
that drives the modem Internal(SCT).
INS
Insert Stream: Sets the buffer clock to the Insert stream. Available in
INSERT MODE ONLY.
CONFIG: CLOCKS
Æ RX-BUFFER/CLOCK Æ BUFFER-SIZE
On the bottom line, Buffer-Size indicates the size in bytes (and size in milliseconds) of the
Plesiochronous/Doppler Buffer. Edit each digit of the buffer size by using the [
←][→] arrow
keys to select the digit to edit, then use the [ ↑][↓] arrow keys to revise that digit. Press [ENT]
when done.
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 ms for D4 (6 ms for ESF)
2048 kbps (E1) or open network D&I at E1 1024 bytes or 4 ms
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