85 lines
4.3 KiB
Plaintext
85 lines
4.3 KiB
Plaintext
MiniSport Laptop Hacker - Vol 9 6 Mar 1993
|
|
|
|
>>> POOR MAN'S PACKET (PMP) ON THE MINISPORT.
|
|
Here's the schematic for the Poor Man's Packet on the Zenith ZL1 or ZL2
|
|
MiniSport Notebook computers. The notations on this schematic are styled
|
|
after schematics provided by VE3SYB or VE3RJO (the reference wasn't clear)
|
|
in WB9BBC's PMP Newsletter Volume 2 Number 5.
|
|
|
|
RX CARRIER
|
|
BIAS DETECT
|
|
+5v 1 o-----------------------+-----+-----+
|
|
/ | /
|
|
\<-+ | +->\ 2x100K TRIM-POTS
|
|
/ | | | /
|
|
# | | | #
|
|
| | |
|
|
-------------
|
|
| 7 1 10 | XTAL
|
|
CTS 14 o----------------------|8 16|---+---|(--+
|
|
| | === 33pf |
|
|
DTR 13 o----------------------|14 15|---+---|(--+
|
|
| TCM | #
|
|
DSR 16 o----------------------|3 4|----|(----------+--+--+--o RX
|
|
| 3105 | .47 | | |
|
|
GND 8&4 o--+ +--/\/\/\-----|2 | 2x1N914 /\ /\ /
|
|
| | 18k | | | | \ 33
|
|
# | +5v +--|5 11|----|(--/\/\/+ | | /
|
|
| o | | 9 12 13 | .1 39K | +--+--+
|
|
| | | ------------- | #
|
|
| \ | | | | |
|
|
| 10k / | +--+--+ /
|
|
| \ | # 20K \<---|(-----o TX
|
|
| / | / .1
|
|
| C +---+ #
|
|
| | +-----o PTT
|
|
| / |
|
|
| B |/ |
|
|
+---| 2N3904 / C
|
|
|\ 4K7 B |/
|
|
\ E -----/\/\/---+---| 2N3904
|
|
| / | |\
|
|
# / / \ E
|
|
/ 22K \ |
|
|
RTS 15 o-------------------------------- / #
|
|
#
|
|
|
|
|
|
CONNECTION = o or + /
|
|
/ |/
|
|
RESISTORS = /\/\/ or \ TRANSISTORS = --| B, E and C are marked
|
|
/ |\
|
|
CAPACITORS = |( or = \
|
|
|
|
DIODES = /\ or \/ GROUND = #
|
|
|
|
Other PMP schematics show how you can hook LED monitors onto pin 3 of the
|
|
3105 (a Packet DCD indicator), and the PTT line (transmit light). The PTT
|
|
line goes into my Kenwood TH21AT, which requires no pullup resistor on the
|
|
collector of the transistor. YOUR RADIO MAY REQUIRE A PULLUP OR MAY RE-
|
|
QUIRE PTT TO PULL THE DC LEVEL OF THE TX LINE. See other PMP documentation
|
|
for these complications.
|
|
|
|
I used 1Mohm pots instead of the two 100k pots. These two must be 10 or 15
|
|
turn precision. The 39kohm resistor added in line with the TX audio is
|
|
shown on no other schematics I've seen; I needed it to cut the audio down
|
|
so that the 20kohm pot could be run about mid-range with my Kenwood TH21AT.
|
|
I used some old junky GE-10 transistors. These worked fine except on the
|
|
PTT line. I substituted in a 2N2222 on the PTT line.
|
|
|
|
Using this hardware, some changes to the "PMP.CFG" file have to be made to
|
|
direct software to the ZL2 COM2 port. In a nutshell, we need to aim PMP at
|
|
the 8250-compatible registers and bits I spoke about in the last newslet-
|
|
ter. Look at the previous two issues and compare to these necessary lines
|
|
in PMP.CFG:
|
|
|
|
pttport 0x2fc 2 0
|
|
txport 0x2fc 1
|
|
cdport 0x2fe 0x20 0
|
|
rxport 0x2fe 0x10
|
|
|
|
No "init" lines are necessary because of the availability of *real* power
|
|
on the MiniSport COM2 header (see last issue of MLH).
|
|
|
|
73, Brian, ka9snf@wb7nnf.#spokn.wa or Internet ka9snf@jupiter.spk.wa
|