Carrier Access Access Bank II SNMP - Manual (Page 112)

TP Busy/Idle Switch
9/24/01 11-9
Table 11-5: 4-Position DIP Switch Settings
11.9 TP Busy/Idle Switch
Use switch 4 to select whether the tip-ground relays are closed (busy) or open (idle) during trunk pro-
cessing. (Trunk processing occurs when the T1 line is in an alarm or reset state.) The Busy position
(OFF) causes the tip-ground relays to be closed during a T1 alarm or reset period. The Idle position
(ON) causes the tip-ground relays to be open during a T1 alarm or reset period.
11.10 Setting Transmit and Receive Gain
The transmit (analog-to-digital) and the receive (digital-to-analog) gain for each voice channel can be
set independently using twelve 10-position DIP switches on top of the 4-wire E&M card circuit
board. Each analog channel uses a bank of ten DIP switches, with five for transmit and five for
receive. The gain from each switch is additive, with switches 1-5 providing transmit (analog-to-digi-
tal) gain of 1, 2, 4, 8 and 16 dB, respectively. Switches 6-10 set receive (digital-to-analog) gains of 1,
2, 4, 8, and 16 dB, respectively. With all five switches off, the gain is -21dB. Because the gain from
the switches is additive, any gain level between -21dB and 10dB is possible.
The digital transmission level is limited by the codec to a maximum of 3.17dBm0. The gain stages
may be set to apply up to 10dB of gain; however, the maximum level of the codec must not be
exceeded or distortion will result.
The analog transmission level may be set to a maximum 9.5dBm before distortion begins to occur.
11.11 Transmit (Analog-to-Digital) Gain
A transformer provides the analog input (T, R) from the 4-wire voice connections to the Access Bank
II - SNMP. The gain from each switch on the 10-position DIP switch is additive, with switches 1-5
providing gain of 1, 2, 4, 8 and 16 dB, respectively. To calculate the T1 transmit level, use the follow-
ing formula:
T1 level = Analog Input level + å Gain Switches - 21
The following is an example of setting transmit gain:
Suppose the analog input level is at +3dBm. With all switches off, the level at the T1 line is +3dBm -
21db = -18dBm0. To set a 0dBm0 level at the T1 line, switches 2 and 5 (gains 2dB, and 16dB) must
be turned on. The level at the T1 line is then:
Switch Number ON OFF
1 N/A Normal E&M
2 N/A N/A
3 N/A N/A
4 TP Idle TP Busy