This thread, captured from the IBM Communications Forum,
       10/93, provides some information on modem 'v' standards and
       the "bis" designation. What do  'v standards' and 'bis' mean,
       where do they come from and why are they important to me?
       Edited: Steve McCoy, 76702,1156.



       #: 242477 S4/FAX [C]
           29-Sep-93  21:15:26
       Sb: Bis???
       Fm: Lloyd Schulman 76314,3344
       To: all

       I am looking to buy a 14.4 send, receive fax/data modem. What
       is (bis), I see advertisments for V.32 & V.42 and some with
       both, what is this and what should I look for? Thanks


       #: 242650 S4/FAX [C]
           30-Sep-93  09:02:17
       Sb: #242477-#Bis???
       Fm: earle robinson [eurfor] 76004,1762
       To: Lloyd Schulman 76314,3344 (X)

       All 14.4 fax modems also have v.32bis and v.42 (and,
       v.42bis). Here's a brief explanation of the more common v
       standards:

       v.42         CCITT error control
       v.42bis      CCITT compression (requires v.42 to be active)
       MNP 2-4      Older, but widely used error control method
       MNP Class 5  Compression under MNP. Less efficient v.42bis
       V.22bis      CCITT standard modulation for 2400 bps
       V.32         CCITT standard modulation for 9600 bps
       V.32bis      CCITT standard modulation for 14400 bps
       V.29         CCITT std half duplex 9600 bps for faxing
       V.17         A new CCITT std, offers 14.4k bps for faxes


       #: 242715 S4/FAX [C]
           30-Sep-93  13:05:33
       Sb: #242650-Bis???
       Fm: Stephen Satchell 70007,3351
       To: earle robinson [eurfor] 76004,1762

            Good list.  Here are some additions to it:

       V.34    Draft Recommendation for 28.8-kilobits/s (V.fast)
       MNP 10  ACE -- Adverse Channel Enhancement -- for cellular
       V.14    Async/Sync converter (for direct and buffered mode)

       Regarding your comment on MNP2-4, that is considered an
       "alternate" protocol in V.42.  Thankfully, I haven't seen a
       modem with "just" MNP, so unless there is a problem in the
       handshaking of the modem just about every modem sold in the
       past two years will make a V.42 (LAPM) connection.

       Lurkers:  If you see "ALT" or "MNP", in many cases you have a
       problem.  Unless you happen to be calling MCI Mail and still
       get connected to older Microcom modems.


       #: 242969 S4/FAX [C]
           01-Oct-93  06:12:49
       Sb: #242715-Bis???
       Fm: earle robinson [eurfor] 76004,1762
       To: Stephen Satchell 70007,3351 (X)

       After posting that message, I added v.34 to that stuff, which
       I keep with other kinds of verbiage, in an infoselect file
       which I pop up over my editor, then drop into messages as
       required.  Since mnp10 is quite special, and not that much
       used, I don't like to confuse people.  After all, some
       microcom modems support mnp7, too.  As for v.14, you are
       right, but for that type of message, again it would confuse.

       As for your message to lurkers, there are more cases than mci
       mail which will give you an mnp connection.  These include
       infonet 2400 bps nodes, CompuServe's 2400 bps nodes, some
       v.32 national networks in europe, etc.


       #: 243061 S4/FAX [C]
           01-Oct-93  12:15:58
       Sb: #242650-Bis???
       Fm: George Mount 75300,2226
       To: earle robinson [eurfor] 76004,1762

       Not all true.  Not all 14.4 fax modems support V.32.  They
       are not really related.  14.4 fax is V.33 and V.17 if
       properly implemented, with of course the older fax standards
       V.27 and V.29.

       V.32 has nothing to do with fax.


       #: 243368 S4/FAX [C]
           02-Oct-93  15:25:57
       Sb: #243061-Bis???
       Fm: earle robinson [eurfor] 76004,1762
       To: George Mount 75300,2226

       I'm quite aware that v.32 has nothing to do with faxing.

       But, 14.4 fax is v17, but not v.33, which is a data
       modulation, 4 wires.

       Though there are many fax modems that support 9600 bps faxing
       (v.29), but only v.22bis (2400 bps) data, I know of no modem
       that offers v.17 fax (14.4) without also offering v.32bis.
       And, since v.32bis is backward compatible with v.32, this
       latter is also supported.

       Finally, it is v.27ter which is used as the intermediate
       fallback speed for faxing, not v.27, with v.21 as the lowest,
       300 bps.


       #: 242676 S4/FAX [C]
           30-Sep-93  10:02:43
       Sb: #242477-Bis???
       Fm: Don Hinds 76004,612
       To: Lloyd Schulman 76314,3344 (X)

       'bis' means something like next or more. There was v32 (9600)
       and bis means more, ie 14,400. So it's faster than a v32
       which is 9600 or slower only.


       #: 243022 S4/FAX [C]
           01-Oct-93  10:51:46
       Sb: #242676-Bis???
       Fm: Randy Bradakis 71441,3672
       To: Don Hinds 76004,612

       'bis' means 'TWO', 'ter' means 'THREE', etc... V.32bis means
       V.32 revision two. V.32ter means V.32 revision three...
       V.32terbo is the 'cute' name for V.32ter


       #: 243414 S4/FAX [C]
           02-Oct-93  18:00:31
       Sb: #242676-Bis???
       Fm: Richard Donkin 100272,1772
       To: Don Hinds 76004,612

       Actually, bis and ter roughly mean A and B in French - e.g.
       if there are houses numbered 15 and 16, two houses built
       between them might be numbered 15bis and 15ter.

       CCITT (as it was) seemed to use French as one of its
       languages - certainly its name was French.