SVXLINK and Hardware
This post is about hardware and the SVXLINK Voice System.
- SVXLINK in general does not need any hardware and can be wired directly
- CAUTION: When wiring directly into the Soundboard.
- It is probably best to use some interface between the Transceiver and Computer Soundboard.
It is possible to connect your Transceiver directly to the Computer. SVXLINK uses the RS232 (RTS or DTR) only to key the transmitter. The (DCD or DSR) is to detect a carrier from a receiver. This signal is present when the receivers squelch is open. The audio from and to the transceiver can be connected directly to the Sound Board. This is probably the most flexible connection,because the Software does the controlling. With appropriate TX / RX it can configure the RF Hardware as Simplex Link or as Repeater without the need of a repeater controller.
CAUTION:
Since most Transceiver can produce high power on their Audio connection it can destroy your Soundboard input. This may not happen immediately and stretch over longer period of time. Consider, that even the Speaker connector provides higher levels of audio. The Sound board “Mic” input is very sensitive and when over driven may suffer permanent damage.
It is advisable to use the “Line In” of the Sound Board input instead. The Line In was designed to handle higher levels and may be better suited for this task. The safest way is to use some sort of minimal interface.
EI-160 with audio ALC
The EI-160 is a VoIP interface specifically designed to interface Radio Transceiver with the Computer Hardware. It was designed using a Micro controller with 16 MHz clock, has Timeout Timers, DTMF receiver, options to connect Carrier detect and more.
Sound Board Interfaces are designed to compensate for unsafe signal levels. Aside, many devices will isolate the Computer Hardware from the Radio Transceiver and thereby reduce computer generated noise. The Audio signal is separated by a transformer (Galvanic Isolation) and the Carrier detect, PTT keying circuits are in many cases Optically isolated. This is the safest way to connect your Computer to your Radio Transceiver. Unfortunately, so called Optocoupler require a significant drive current, that some Radios (COS, CAS, COR) circuits can’t provide. Mostly the Radios that switch between 0 and 5 Volt aren’t designed to drive more than a few milliamps.
