Interface
Balanced Audio Computer Interface With Hardware PTT
For transceivers requiring balanced, differential, and/or DC isolated audio.
The audio section of this interface may also be used for broadcast quality 600 ohm impedance audio connections between a computer and any audio source or input.
Balanced Audio Interface schematic
FUENTE: http://hflink.com/interface/#simple
Isolated ALE Interface: Audio, CAT, Hardware PTT, Speaker Mute
PCALE APPROVED
The following interface circuit provides RF, DC, and AC isolation between the signals of computer and the radio, and between the grounds of the computer and the radio. It is recommended for use with PCALE and other ALE controllers. The interface has all features needed for ALE, including:
1. Audio transformer isolation
2. Opto isolation of the computer control signals
3. Speaker muting (operator alerting / channel monitoring when called by other stations
4. Transmit inhibit switch to prevent undesired computer processes from transmitting
5. CAT control of Icom radios.
Click on the schematic to zoom:
Parts for the Isolated ALE Interface
Like the previously described Simple ALE Interface, this Isolated ALE Interface is made from common parts, while keeping total parts count to a bare minimum. New parts for this circuit may be acquired at some local electronic parts stores (where they still exist) or via online electronic parts stores such as Digikey or Jameco. Homebrewers are encouraged to recycle parts from old equipment... many of these parts may be found in the junkbox, or scavenged from old consumer computer peripherals, telephones, radios, or telephone answering machines. Links to download the datasheets / and spec sheets PDF files for the optocouplers, relays, and transformers are in the Parts List.
For part substitution, most of the parts and part values are not critical, and a lot of leeway for the homebrewer is provided in the design. For example, almost any of the common 6-pin opto coupler ICs may be substituted in the circuit. The transformers may be substituted with almost any small audio transformer, various impedances (100 ohms, up to 50k ohms or so) and even a speaker transformer from an old transistor radio... but 1:1 transformers with impedances of about 600 ohms or 10k ohms will probably work best (such as a telephone modem transformer). The relay may be almost any low power 12VDC coil relay that has Double Throw. The power to run the relay is taken from the transceiver's switched 13.8VDC output, normally found on the transceiver's rear panel accessory connector, or it may be taken from the main 13.8VDC supply (through a 1 amp fuse). Alternatively, a relay with a different coil voltage may be substituted with an appropriate DC supply to match the coil voltage of the relay... or an appropriate value and power of resistor may be inserted in series with the relay coil to substitute a low voltage coil, such as 5V coil, running on a 12V supply.
Isolated ALE Interface - Parts List
C1 1000PF CERAMIC, 50VDC
C2 10UF 16VDC
C3 1000PF CERAMIC, 50VDC
C4 10UF 16VDC
C5 10UF 16VDC
D1 1N4004 OR SIMILAR DIODE
J1 MINI STEREO PLUG MALE, 3.5MM
J2 MINI STEREO PLUG MALE, 3.5MM
J3 MINI STEREO PLUG MALE, 3.5MM
J4 DB9 CONNECTOR FEMALE CABLE CONNECTOR, WITH SHELL
J5 MINI STEREO PLUG MALE, 3.5MM
K1 RELAY SPDT 12VDC COIL (TAKAMISAWA SY-12-K, OMROM G5V-1-12VDC, OR SIMILAR)
R1 1K RESISTOR 1/8W
R2 1K RESISTOR 1/8W
R3 10K POTENTIOMETER 1/8W, PCB MOUNT, TRIMMER
R4 4.7K RESISTOR 1/8W
R5 4.7K RESISTOR 1/8W
R6 10K POTENTIOMETER 1/8W, PCB MOUNT, TRIMMER
R7 4.7K RESISTOR 1/8W
R8 1K RESISTOR 1/8W
R9 1K RESISTOR 1/8W
R10 1K RESISTOR 1/8W
SP1 SPEAKER 4 TO 16 OHMS, 4WATTS, WITH ENCLOSURE
SW1 SPST SWITCH ON/OFF, TOGGLE
T1 AUDIO TRANSFORMER 1:1 (TAMURA TTC-5023, TRIAD TY-141P, OR SIMILAR)
T2 AUDIO TRANSFORMER 1:1 (TAMURA TTC-5023, TRIAD TY-141P, OR SIMILAR)
U1 OPTOCOUPLER 4N25, H11A1, OR SIMILAR
U2 OPTOCOUPLER 4N25, H11A1, OR SIMILAR
U3 OPTOCOUPLER 4N25, H11A1, OR SIMILAR
W1 COAXIAL CABLE RG-174
W2 COAXIAL CABLE RG-174
W3 COAXIAL CABLE RG-174
W4 COAXIAL CABLE RG-174
MISC WIRES
MISC CABLES
MISC TRANSCEIVER REAR PANEL ACCESSORY CONNECTORS
FUENTE: http://hflink.com/interface/#simple