[App_rpt-users] Cheap USB Fobs

Doug Bade kd8b at thebades.net
Wed Sep 29 11:38:59 EDT 2010


JMTek is the vendor for the SS1623 chipset. This chipset works well in
windows and other Linux applications such as pcrepeatercontroller etc.. as a
high quality high scan rate device... It is unfortunate it does not work for
App_rpt at this time. It does seem to be the currently available successor
to the C-Media chip family being found in many sound fobs coming in to the
U.S. at this time.. They do work well in many other amateur radio type
projects going on.... In general they perform as well as C-Media devices...
other than using another driver... the I/O pin may or may not be there that
is used for the PTT, I have not investigated that as I use URI's for App-rpt
systems I am building...

Doug
KD8B 

-----Original Message-----
From: app_rpt-users-bounces at qrvc.com [mailto:app_rpt-users-bounces at qrvc.com]
On Behalf Of Ken
Sent: Wednesday, September 29, 2010 10:07 AM
To: 'Yokshs'; app_rpt-users at qrvc.com
Subject: Re: [App_rpt-users] Cheap USB Fobs

Yes ... it took at >month for me to get mine and even though the package has
CM-108 written right on it, the chip is identified by Linux as JMTek (HY559
chip I think).  I sent an e-mail expressing my disappointment (which was
un-acknowledged by Dealextreme).

I found if you modify the vendor codes in usb_radio.c so that the program
thinks this JMTek is actually a C-Media unit, it will scan the fob and read
audio.  It will not turn the red light on for transmit though ... which is
immaterial anyway, since you cannot get at the wire you need inside the
'blob' to use for PTT.  I think it could be used for my weather radio
application, but the software changes would be a  bit tricky (for me) making
some if/and/or logic more complicated - getting the arrangement of left and
right parenthesis correct eluded on the first try.  

I have one other source on the way now, which would be the preferable
solution (no software mod needed). But I will not be surprised if it turns
out to have the wrong chip.

Ken

Buyer beware, as usual.
www.dinodirect.com/sound-card-adapter-usb-cm108-chipset.html?ddse=CM-108



> -----Original Message-----
> From: app_rpt-users-bounces at qrvc.com [mailto:app_rpt-users- 
> bounces at qrvc.com] On Behalf Of Yokshs
> Sent: Wednesday, September 29, 2010 9:43 AM
> To: app_rpt-users at qrvc.com
> Subject: Re: [App_rpt-users] Cheap USB Fobs
> 
> 
> I received my CM108 fobs yesterday. I ordered them from:
> http://www.dealextreme.com/details.dx/sku.21812
> 
> I haven't had much time to play with them yet, but the IC is a "blob"
> much
> like the cheapo Ebay fobs.
> 
> Has anybody had the same problem?
> 
> 73.
> 
> Kyle
> K0KN
> 
> _______________________________________________
> App_rpt-users mailing list
> App_rpt-users at qrvc.com
> http://qrvc.com/mailman/listinfo/app_rpt-users

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