[comp.sys.ibm.pc.misc] Question-Modem/voice line switchers

uukx@vax5.cit.cornell.edu (04/02/91)

Can someone explain how those fax/modem/voice line switchers work?  Especially
the modem/voice part.  How can a device determine whether to route a phone call
to a modem, or to the telephone, and how does it ring the phone once it has
picked up the phone and determined it was a voice caller?  Also, is it
transparent to the caller on the other end?

I am wondering if it would be practical to buy one of these devices to run a
BBS on a single phone line...Besides the inconvinience of having the line tied
up, would it be possible for voice callers and modem callers to use the same
line hamoniously?

Any info would be appreciated...thanks
-Stephen

py@meadow.uucp (Peter Yeung) (04/03/91)

In article <1991Apr2.015541.3801@vax5.cit.cornell.edu> uukx@vax5.cit.cornell.edu writes:
>Can someone explain how those fax/modem/voice line switchers work?  Especially
>the modem/voice part.  How can a device determine whether to route a phone call
>to a modem, or to the telephone, and how does it ring the phone once it has
>picked up the phone and determined it was a voice caller?  Also, is it
>transparent to the caller on the other end?
>

There are, in general, 3 types of such switch and they typically treat
voice and modem the same:

(1) a synthesised voice will ask the called to press some code on a touch tone
    phone to indicate whether it is a voice call or something else. If it has
    3 ports then it can handle voice/modem/fax.

(2) the switch answers the call and check for the incoming fax tone (newer
    fax machines always generate an id tone when calling), if a tone is
    detected within a certian period then it switches to the fax port, 
    otherwise it switched to the voice/modem port.

(3) the switch identifies the incoming call by a distinct ring. The "distinct
    identification ring" service must be available in your area. When you
    subscribe to the service, you will have another number on the SAME phone
    line. When a call on the new number comes in, it will have a different
    ring (2 short ring instead of 1 long ring) such that you or the switch
    can tell which number was called.

I have the third type but somehow it does not work for me (going to check
with the store see if anything can be done). According to the store, all
units sold seemed to work B-(
    

>I am wondering if it would be practical to buy one of these devices to run a
>BBS on a single phone line...Besides the inconvinience of having the line tied
>up, would it be possible for voice callers and modem callers to use the same
>line hamoniously?
>
>Any info would be appreciated...thanks
>-Stephen

I think type (3) switches may work for you (see the note on my experience) since
it does not care what is actually calling. Type (2) switches can only tell
voice calls from fax calls. I think some can handle modem call as well but the
caller has to send a touch tone to id it is a modem call instead of a voice
call. I have only seen type (1) switch once and it is usually not too
popular.


-- 
Peter Yeung     Amdahl Canada Ltd., Software Development Center
                2000 Argentia Road, Plaza 2, Suite 300
                Mississauga, Ont.   L5N 1V8
                Phone: (416) 542-6300    Fax: (416) 858-2233

py@meadow.uucp (Peter Yeung) (04/05/91)

In article <1991Apr3.153518.7049@meadow.uucp> py@meadow.UUCP (Peter Yeung) writes:
>In article <1991Apr2.015541.3801@vax5.cit.cornell.edu> uukx@vax5.cit.cornell.edu writes:
>>Can someone explain how those fax/modem/voice line switchers work?  Especially
>>the modem/voice part.  How can a device determine whether to route a phone call
>>to a modem, or to the telephone, and how does it ring the phone once it has
>>picked up the phone and determined it was a voice caller?  Also, is it
>>transparent to the caller on the other end?
>>
>
>There are, in general, 3 types of such switch and they typically treat
>voice and modem the same:
>
> ... description of type (1) & (2) deleted ...
>
>(3) the switch identifies the incoming call by a distinct ring. The "distinct
>    identification ring" service must be available in your area. When you
>    subscribe to the service, you will have another number on the SAME phone
>    line. When a call on the new number comes in, it will have a different
>    ring (2 short ring instead of 1 long ring) such that you or the switch
>    can tell which number was called.
>
>I have the third type but somehow it does not work for me (going to check
>with the store see if anything can be done). According to the store, all
>units sold seemed to work B-(
>    

The first unit I bought does not work with the "distinct rings" in my area.
That unit requires the distinct ring to be less than 1.5 sec (regular rings
are 2 sec. followed by a pause of 4 sec.). Somehow, the distinct rings in my
area is two long rings with a short pause inbetween. The store I bought the
unit form referred me to a manufacturer of another model which is not being
carried by them. That model adjusts to different types of distinct rings
as long as they are different enough from from the regular ring. It works
fine now and I recommend it highly, their address follows.

    UNiPLUSE International Inc.
    60 West Wilmot Street, Unit 17
    Richmond Hill, Ontario
    Canada L4B 1M6

    Phone: (416) 886-5659
    Fax:   (416) 886-5455

The sales manager there took his time to explain to me the whole bit of
"phone rings" and the principle of their units.

Disclaimer: I am not related to them in any way, I am just a satisfied customer.
    

-- 
Peter Yeung     Amdahl Canada Ltd., Software Development Center
                2000 Argentia Road, Plaza 2, Suite 300
                Mississauga, Ont.   L5N 1V8
                Phone: (416) 542-6300    Fax: (416) 858-2233