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Path: utzoo!watmath!clyde!cbatt!ihnp4!inuxc!pur-ee!uiucdcs!uiucdcsb!kkim
From: kkim@uiucdcsb.UUCP
Newsgroups: comp.dcom.modems
Subject: 2400 bps modems
Message-ID: <167100003@uiucdcsb>
Date: Mon, 9-Feb-87 14:19:00 EST
Article-I.D.: uiucdcsb.167100003
Posted: Mon Feb  9 14:19:00 1987
Date-Received: Wed, 11-Feb-87 07:54:29 EST
Lines: 48
Nf-ID: #N:uiucdcsb:167100003:000:1930
Nf-From: uiucdcsb.cs.uiuc.edu!kkim    Feb  9 13:19:00 1987


/* Written  1:23 pm  Feb  5, 1987 by kkim@uiucdcsb.cs.uiuc.edu in uiucdcsb:misc.consumers */
/* ---------- "2400 bps modems?" ---------- */
    I am considering buying a 2400 bps modem.  I looked up Byte magazine and
I found following ones which seem relatively cheap:

    1. Eclipse 2400 External EDP-2400                $299
    2. Anchor Lightning                              $299
    3. THE 2400                                      $259
       (Thompson, Hariman, and Edwards)
    4. CTS 2424 ADH async/sync                       $269
       (CTS Fabri-Tek Inc., Datacomm Produce Division)
    5. Incomm (upgradeable to 4800)                  $295

Do you have any good or bad experience with them?
   
By the way, what kind of modulation is adopted in 2400 modems?  An article in
Byte said 600 baud * 4 (QAM) = 2400 bps based on the CCITT V.22bis method.
Is it the method almost all of 2400 bps modems adopt?

How about 1200 baud modems using Bell 212 (or 212A) method?
In some book, I saw that it uses FSK(Frequency Shift Keying); the manual
of my 1200 bps Anchor Volksmodem 12 says that it uses PSK (Phase Shift
Keying) without saying how-many phase(2-phase or 4-phase).
The same article in BYTE says that 600 baud * 2 (4-phase PSK) = 1200 bps.
Which one is correct?

Do you have any correct information?  Or did it change as time goes on?

                            Kyongsok KIM

                            Department of Computer Science
			    University of Illinois at Urbana-Champaign

my addresses are as follows:

    	network		address
        -------		-------
        arpanet		kkim@b.cs.uiuc.edu (domain format) OR
          	        kkim@uiuc.arpa  (alias)

        csnet		kkim@uiuc.csnet,
      			kkim%uiuc@csnet-relay.arpa (obsolete), OR
		        kkim%uiuc.csnet@csnet-relay.arpa (obsolete)

        usenet/uucp	{seismo, pur-ee, ihnp4, convex}!uiucdcs!kkim

/* End of text from uiucdcsb:misc.consumers */