Reference10:Interfaces/FXS/Advanced
There are also other versions of this article available:
Reference10 (this version) | Reference11r2 | Reference12r1
The advanced settings of the analogue interfaces can be made here:
| Optimization grade: | As per default the TEL ports are optimized for low power consumption (Optimization 'high' and 'mid'). This decreases the usual on-hook supply voltage of 48V down to 24V. Most conventional phones and faxes can deal with this. In case a special phone is connected that cannot deal with this low voltage or if a long cable is used this dropdown can be modified. 'high' and 'mid' both set 24V on-hook voltage. The off-hook loop current is set to 20mA. 'low' sets 48V on-hook-voltage. |
| Ringing Voltage | This topic modifies the ringing voltage used for ringing. Ringing frequency is 25Hz. 'low' sets 65Vpk/45Vrms, 'mid' sets 68Vpk/48Vrms and 'high' sets 70Vpk/49,5Vrms AC. |
| Loop length | present on ip28 gateways only Loop length can be set to 'low' for 500ft/155m or 'high' for 5000ft/1550m. Checking this topic to 'high' decreases ring-trip threshold by 20% so that off-hook detection becomes more sensitive. |
| RingTrip Threshold | present on ip22/24/302/305 gateways only Ring-Trip threshold can be adjusted using an absolute value in milliamperes. |
| Loop Current | present on ip22/24/302/305 gateways only Loop current can be adjusted using an absolute value in milliamperes. |
Note: there is no difference between PoE and PSU powering of the IP2x.
For possible line lengths, see Maximum wire length.