[App_rpt] app_rpt setup and requirements.

Jim Duuuude telesistant at hotmail.com
Mon Oct 9 02:01:18 EDT 2006

First of all, analog telephone sets are FAR from full duplex devices (look 
at one through a sweep
generator sometime). A pure 2/4 wire hybrid (a real analog one), even in its 
best practical
(and expensive and heavy with transformers, etc) configuration is WAY far 
from perfict. Between
a telephone set and an FXS interface of todays (poor) quality, the 
transhybrid loss is not ever
expected to be better then 20 db or so, and then only on good days.

The bottom line is that being able to do real full duplex (which is 
ABSOULTELY necessary for
a radio system) is just not feasable on a 2 wire interface. So you need a 4 
wire one.

Most channel banks and other channel termination devices generally only come 
in FXS and FXO
these days (not many 4 wire E&M or SF trunks around anymore), so the idea 
was to interface
to something available and practical. 1 loopstart (for receive) and 1 
groundstart (for transmit)
FXS interface does the trick really nicely.

The ARIB board is there to adjust audio levels and impedances between the 2 
FXS interfaces
and the receiver and transmitter of repeater RF hardware. Also it takes in 
typical keying signals
(such as COR/PL decode) and outputs PTT to key the transmitter, based upon 
loop condition
of the 2 FXS circuits. A radio system is just not typically able to swallow 
a telco loop with
DC current on it raw.

Different radios have different needs for levels, De-emphasis, etc. The ARIB 
card takes care of
all of that for you.

The different interface methods (ARIB board, PCI card, etc), are all 
designed to be a more or
less generic interface to 2-way RF hardware. Certainly the Micor, 
Maxtrac/Radius, Mitrek, etc
all are more then capable (and we use all of them ourselves) of being used 
with any of our

The Doug Hall RBI-1 is an interface controller (now extinct) that directly 
interfaces with
Kenwood mobile radios, such as the TM-241, TM-331, TM-441, TM-541 (which are 
extinct). IT allows the radios to be programmed (their frequency, mode, etc) 
in real time
from a remote-base controller, such as app_rpt. They were a wonderful device 
in their time.

Modernly, we support the Yaesu Radios that have a CAT interface (Which, 
are only the larger mulitband HF-440 radios), such as the FT817/857/897. 
Also we are
just finishing suport for the Kenwood TM-G707 for those that just want a 
2m/440 remote
for less money. The Yaesu radios are nice (since they cover about 
everything), but are
sometimes not cost effective. And yes, of course, we do support the 
ALL of their bands, including 6m/144/440, even on sideband.

Basically our intention is eventually to support all of the affordable 
radios that have
remote control from a PC device possible and accessible. I wish more 
would make this functionality available on the less expensive radios.

I hope I have answered all your questions


>From: "Eric Fort" <eric.fort at gmail.com>
>Reply-To: Asterisk Repeater Controler <app_rpt at lists.illiana.net>
>To: "Asterisk Repeater Controler" <app_rpt at lists.illiana.net>
>Subject: [App_rpt] app_rpt setup and requirements.
>Date: Sun, 8 Oct 2006 19:11:10 -0700
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>Hopefully those on the list can answer a few questions about getting 
>setup and what is really required.
>1.  why is the arib needed and what exactly does it do?
>2.  Why do I need 2 fxs ports for full duplex operation?  my phone is full
>duplex when plugged into the same port why can't the audio for the radio
>be?  Come to think of it I can buy a little phone with a headset jack for
>next to nothing and have seperate tx (mike) and rx (speaker) audio.  this
>just takes a 2 to 4 wire hybrid common to most phones.  why do I need the
>arib at all?
>3.  Why do I need the arib at all?
>4.  is the rbi-1 really needed?  what function does it serve?  I've seen
>mention of using an ft-897 directly without it.  How is this done?  why hf
>only for the 897 when the 897 covers hf, 6m, 2m, and 440?
>5.  what about interfacing other radios used for repeaters such as micor,
>maxtrack, etc.
>Eric - kg6kqt

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