piclist 1998\10\26\125540a >
Thread: Telephone Delay
www.piclist.com/techref/pots/dtmf.htm?key=telephone
picon face BY : Peter L. Peres email (remove spam text)



On Mon, 26 Oct 1998, Peter C. Casavant wrote:

> I am designing a system using a PIC micro controller chatting thru a
> Cermetek CH1786LC modem.
>
> The PIC requests a command thru the modem to a PC. The PC returns a command
> of what it wants to do, then the transaction is completed. I want to put a
> time out on waiting for the command, does anyone know what the maximum
> latency of the phone system is, or what an appropriate time out would be
> for this setup? I am limiting connection to V.22bis.

If you want to be thorough, assume the total path delay to be twice around
the globe in a total of 4 sattelite bounces each. Count each bounce (up &
down) == 80e3 km, so 80e3 * 8 = 640e3 km, or <2.2 seconds. Add to this all
the system delays you can think of and some safety margin. That's it.

Most modem-based systems for local calls implement a timeout of 20 seconds
or more for the shortest timeouts anyway.

Peter

<Pine.LNX.3.95.981026194339.498O-100000@plp4.plp.home.org>

In reply to: <3.0.32.19981026085721.006866b4@together.net>
See also: www.piclist.com/techref/pots/dtmf.htm?key=telephone
Reply You must be a member of the piclist mailing list (not only a www.piclist.com member) to post to the piclist. This form requires JavaScript and a browser/email client that can handle form mailto: posts.
Subject (change) Telephone Delay

month overview.

new search...