For example: Cellular Number Prefix: 044, 045 Program the unit to intercept prefixes 044 + 045. If you dial 281-550-5592 (local call); since this number does not have the prefixes 044 or 045 the router will dial out using the land line (PSTN). If you dial 044-788-7621 (cell); the router will switch over to the GSM module and call out via the cellular network creating a Mobile to Mobile call which is much cheaper.

Features:
- GSM quad-band(gsm 850/1900MHz & GSM 900/1800MHz)
- User friendly installation: Plug & Play
- LCR(Least Cost Routing) Feature
- LED indicators for signal strength, status and power
- SIM card locking and Network locking
- Reverse Polarity/12KHz/16KHz metering signal support
- DTMF Caller ID enable and disable
- 1xFXS port and 2FXO ports(one GSM & one PSTN)
- Emergency Battery back-up(optional)
- SMS & GPRS(optional)
- USB Data port for PC connection(optional)

Technical Specifications:
- Air Interface: GSM Phase I/GSM Phase II + compatible
- GSM Frequency: GSM 850/900/1800/1900 MHz
- RF Transmit Power: 2W (900 MHz), 1W (1800 MHz)
- RF Sensitivity: <-103 dBm
- Electricity Power Supply: Input AC100~240V/60Hz; Output DC12V/600mA
- Optional 6-pcs Ni-Mh re-charged Batteries
- LED Indicators; Power / Signal Strength / Network Status / In Use
- Connectors; RJ-11 Interface x2 for telephone and PSTN, USB Interface Jack for PC (Optional), SMA antenna connector, DC power input jack
- Antenna; 2dbi Omni Antenna, High gain antenna and cable as optional


Environment:
- Operating temperature range; -10 to +45 degree C
- Storage temperature range; -25 to +65 degree C
- Humidity; 45% to 95%