JEO 39/46
10. Is it documented?
Yes, it is. The official Jaguar Development System specifications
include an entire "Jaguar Voice Modem" section. The section is 22
pages long, and contains a lot of text, tables, flowcharts, and a
command reference. Below I have included some of them.
11. What are the technical specifications?
Technically, there are a lot of these.
* Voice data is compressed, then sent over the phone lines.
* Game data packets are actually inserted into the voice data. That
is, they interrupt the voice data stream, which serves "to keep
transport latency to an absolute minimum." The way I take that is to
say that any time-critical data will arrive when you expect, since it
pre-empts voice data, not the other way around.
* The following is an interesting table detailing voice vs. data
bytes-per- second. Note the huge increase in data BPS for 19200...
could this be the root of the connection problems for UV at this
speed?
+-------+-------+-------+------+-------+--------+---------+----------+
| Line  | Total | Voice | Voice| Voice | Voice  | Voice   | Remaining|
| speed | bytes | sample| data | packet| headers| bytes   | bytes    |
|       | per   | rate  | rate | size  |        | per     | per      |
|       | second|       |      |       |        | second  | second   |
+-------+-------+-------+------+-------+--------+---------+----------+
| 19200 |  2400 |  7200 | 1800 |    80 |  22.5  | 1822.5  |   577.5  |
| 16800 |  2100 |  6800 | 1700 |    80 |  21.25 | 1721.25 |   378.75 |
| 14400 |  1800 |  5600 | 1400 |    80 |  17.5  | 1417.5  |   382.5  |
| 12000 |  1500 |  4400 | 1100 |    80 |  13.75 | 1113.75 |   386.25 |
|  9600 |  1200 |  3200 |  800 |    80 |  10    | 810     |   390    |
+-------+-------+-------+------+-------+--------+---------+----------+
* Other tables give information about such things as data packet
size, error control information, etc. Mail me if you want me to put
those up.
* The specifications allow for call waiting to only pause games, not
disrupt them. I do not have it (since my computer is not so smart), so
it has not been tested.
* The line speed can be set by software -- in other words, a slower,
more steady rate can be chosen, one that is not as prone to line
errors and hang- ups.
* The "magic" dial tone sequence is not specified. This means,
likely, that different games should have different sequences, so that
they do not try to connect to one another.
* A fully-functional telephone can be made in software, with the
existing command set.
12. What kind of chips and stuff are on the board?
I'll only list the biggest/most interesting looking things, since
there seem to be one to two hundred components on the board. And I'm
not much on chips and stuff, so these are just guesses of the chip
numbers/names...
* Label:
(c) 1995  ATARI CORPORATION      ASSY  700118
ATARI JAGUAR MODEM               ASSY REV 9 (written in)
* 2 chips by Phylon: 1x 0115 P-2 , 1x 0202
* 3 identical chips by Motorola (I assume-- looks like (c) only with
  an 'M'...): MCM6206DJ20-RQQAA9521
Okay, that's enough... If anyone really wants to know... get your own!
Or, just write me!
... They say to beware of pronouns with indefinite antecedents.
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