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Functions
Number of transmit channels
1
2
3-4
5-6
7-8
10-13
14-18
19-24
25-32
Table 16:
Transmitter level depending on the number of transmitter channels
2.9.4
Receiving level
The reception gain is set via the command line interface (CLI).
In case of very noisy lines, the detection level for detecting the useful signal can be raised by 15 dB.
Commands to configure receiving level
< s e t i n t e r f a c e f s k 0 r x a m p l i f y { 0 | 6 | 1 0 | 1 4 | 2 6 } >
< s e t i n t e r f a c e f s k 0 r x i n c r e a s e - d e t e c t { 0 | 1 5 } >
2.9.5
Filter Characteristic
It is possible to choose between high and normal selectivity.
High selectivity is recommended if at low bit rates all possible channels are to be used or
interference with adjacent channels is excessive.
Any desired combination of bit rate and transmit and receiving channel allocations are permitted.
The transmission levels for the individual channels can be set independently of each other.
If normal selectivity is set, the transmit and receive channels should be combined in groups, with
one vacant channel between the blocks. This applies to bit rates from 50 to 200 bps. If there are
different bit rates on the same line, the channels with a low bit rate are to be separated at least by
one low-bit-rate channel from the higher bit rate.
If there are adjacent channels with the same bit rate (applies only to the range 50-200 bps), the
level difference may not exceed 17 dB.
Commands to set filter characteristic
< s e t i n t e r f a c e f s k 0 { r x | t x } s e l e c t i v i t y { h i g h | n o r m a l } >
2.9.6
Two-wire or four-wire line
The 500FSD20 modem features a separate line interface for the transmitter and receiver. For the
two-wire mode, transmitter and receiver use interface NF1, see Fig. 4. Four-wire connection uses
NF1 as output and NF2 as input as shown in Fig. 5.
Commands to set two-wire or four wire mode
< s e t i n t e r f a c e f s k 0 w i r e 2 >
< s e t i n t e r f a c e f s k 0 w i r e 4 >
1KGT151043 V001 1
Transmit Level
-6 dBm
-9 dBm
-12 dBm
-13.8 dBm
-15.6 dBm
-17.2 dBm
-18.6 dBm
-19.8 dBm
-21.1 dBm
Settings
23
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