The phone patch provides an interface between an HF network and the International telephone network, allowing HF stations to be connected to telephone subscribers and vice versa.
The Phone Patch uses a unique adaptive hybrid to convert the four-wire audio from the transceiver to two-wire audio for the phone line. An adaptable hybrid, implemented with digital signal processing (DSP), provides continually recalculated isolation between the off air HF signal and the telephone user, producing a reliable VOX signal (Voice Operated Xmit (transmit)) to key the transmitter when the telephone subscriber’s voice is present. DSP based automatic adaptive hybrid that balances the telephone line continually with no adjustments, eliminating oscillation in full duplex circuits, false VOX tripping and time consuming setup.
General specifications
| Output level to phone line | Nominally 0 dBm |
| Input level from phone line | Nominally 0 dBm |
| Frequency response | 300 to 3000 Hz ±2 dB |
| Output impedance to phone line | 600 ohm |
| VOX sensitivity | Adjustable internally |
| VOX hang time | 0.5 seconds |
| Ultimate hybrid balance | -50 dB measured with a single tone |
| Telephone line connector | RJ-11C |
| Local telephone set connections | RJ-11C |
| Connector to transceiver | DB-25 |
| Indicators | “CONNECT” “OPERATOR OVERRIDE” |
| Front panel controls | “CONNECT” “DISCONNECT” “OPERATOR OVERRIDE” |
| Rear panel control | Monitor volume control |
| Input power | +11 to +15 V DC (12 V DC nominal) |
| Input current | 80 mA @ +12.6 V DC input |
| Size | 185(w) x 270(d) x 70(h)(2000 series standard enclosure) |
| Weight | 0.8 kg |
| Transceiver interface | |
| Rx audio input | Balanced 600 ohm @ 0 dBm |
| Tx audio output | Balanced 600 ohm @ 0 dBm |
| Frequency response | 300 to 3200 Hz ±2 dB |
| VOX key output | Open collector |
| Switching speed | 5 mS |
| Environmental | |
| Operating temperature | -20°C to +55°C |
| Storage temperature | -40°C to +85°C |
| Humidity | Up to 95% @ 55°C |
| Shock | MIL-STD 810G Method 516.6 |
| Vibration | MIL-STD 810G Method 514.6 |
