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The fusion of 2-way radio systems and VOIP


Chan_simpleusb (aka simpleusb) is a lower CPU overhead alternative to chan_usbradio (USBradio). Use when COR and CTCSS are provided by the radio rather than DSP of chan_usbradio. Recommended when using CPUs of less than 1.2 Ghz clock speed or when squelch and CTCSS functions from the radio are desired.

; SimpleUSB configuration


;pp2 = ptt        ; Parallel port PTT on pin 2
;pp10 = cor       ; Parallel port COR on pin 10
;pp11 = ctcss     ; Parallel port CTCSS on pin 11


hdwtype=0		; Leave this set to 0 for USB sound fobs modified using
			; the instructions from usbfob.pdf. Use a setting of 
			; 1 is for Dingotel/Sph interfaces.
rxboost=1		; 0 = 20db attenuator inserted, 1= 20db attenuator removed
			; Set to 1 for additonal gain if using a low-level receiver output

carrierfrom=usbinvert	; no,usb,usbinvert
			; no - no carrier detection at all
			; usb - from the COR line on the modified USB sound fob
			; usbinvert - from the inverted COR line on the modified USB sound fob
                        ; pp - COR using parallel port
                        ; ppinvert - COR using parallel port inverted input

ctcssfrom=no		; no,usb,usbinvert
			; no - CTCSS decoding, system will be carrier squelch
			; usb - CTCSS decoding using input from USB FOB 
			; usbinvert - from the inverted CTCSS line on the modified USB sound fob
                        ; pp - CTCSS decoding using parallel port
                        ; ppinvert - CTCSS decoding using parallel port inverted input

txmixa=voice		; Left channel output: no,voice,tone,composite,auxvoice
			; no - Do not output anything
			; voice - output voice only

txmixb=no		; Right channel output: no,voice,tone,composite, auxvoice
			; See txmixa above.

invertptt=0		; Invert PTT 0 = ground to transmit, 1 = open to transmit
			; This is the collector lead of the 2n4401 on the modified
			; usb sound fob.
			; please refer to the howto for the procedure to do this.

duplex=1		; Full Duplex

;plfilter=yes		; enable PL filter

;deemphasis=yes		; enable de-emphasis (input from discriminator)

Audio levels are set with simpleusb-tune-menu which will save it's settings in simpleusb_tune_usb.conf.

SimpleUSB supports parallel printer port I/O. See

If switching (by hand, non portal config) from USBradio to SimpleUSB do the following:

  • copy /usr/src/astsrc/configs/simpleusb/simpleusb.conf to /etc/asterisk/
  • delete or rename /etc/asterisk/usbradio*
  • delete /etc/init.d/usbradio if Limey
  • touch /etc/init.d/simpleusb if Limey
  • edit /etc/asterisk/rpt.conf rxchannel=SimpleUSB/usb
  • edit /etc/asterisk/simpleusb.conf as desired
  • svcfg if Limey
  • reboot
  • set levels with simpleusb-tune-menu
  • svcfg if Limey

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