Comtech EF Data SNM-1010L - Manual (Page 25)

SNM-1010L Data/Control Modem Revision 0
Introduction MN/SNM1010L.OM
1.3 Call Setup and Teardown Performance
The SNM-1010L significantly improves call setup and teardown performance. The
requirements for different phases of call setup and teardown are as follows (refer to
Figure 1-4 for the call setup and termination phases):
Phase Nominal Time
Modem programming to switch from control to traffic mode < 6 sec
Carrier acquisition (Traffic carrier) See B.4.1
Modem programming to switch from traffic to control mode < 6 sec
Carrier acquisition (Outbound control channel) < 5 sec
Burst Tx
Cont. Rx
19.2 kbit/s
QPSK
R=1/2
Viterbi
Program Modem
Cont. Tx
Cont. Rx
Data Rate
Tx Pwr
QPSK
R=1/2
Viterbi
Modem
programmed
Carrier acquisition Carrier locked
Traffic ckt. active
Program Modem
Burst Tx
Cont. Rx
19.2 kbit/s
Tx Pwr
QPSK
R=1/2
Viterbi
Modem
programmed
Carrier acquisition
Burst Tx
Cont. Rx
19.2 kbit/s
QPSK
R=1/2
Viterbi
Switch from control to traffic mode Switch from traffic to control mode
Terminate
Command
Carrier Detect
Traffic
circuit freq.
& tx pwr
received
from NMS Carrier Detect
Control
Mode
Traffic
Mode
Control
Mode
Figure 1-4. Call Setup & Termination Phases
1.3.1 Maximum Inter-call Delay
The maximum inter-call delay (i.e. maximum delay from the end of a call to the start of a
new call) is:
• < 2 seconds for calls terminated due to RTS deactivation.
• < 4 seconds for call terminated due to loss of carrier. (Assumes operator
configurable carrier loss timeout is set to 2 seconds.)
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