Computer Control Interface not only for AR8200
MK2 compatible !
I redesigned this interface to more universal form. Now have LED's to indicate data flow. Interface can be used for every device which need to convert TTL to RS232 levels. For example scanner, cellular phone, digital diary and many, many more. You only need to change cable with canon connector on one side and connector for specific device on other side, converter remains same.
For AR8200 you must obtain original OS8200 lead or cheaper synch cable for palmtop HP Jornada from local Hewlett-Packard reseller . Product number is "HP F1258A". Cable price is around $20 (750 Kc v AutoContu). Here are some pictures how this cable look like:
In the tables below are pinout details of
AR8200 socket (for both versions), original OS8200 cable and HP cable. Signal connections are taken
from service manual. Pin numbers are reading top to bottom when looking at the
AR8200 socket
|
AR8200 MK1 and
early MK2 pinout |
Use |
OS8200 |
HP600 |
HP600 |
|
1 |
+5V |
Red |
Yellow |
4 |
|
2 |
TXD |
White |
Orange |
3 |
|
3 |
RXD |
Black |
Red |
2 |
|
4 |
GND |
Yellow |
Blue/brown |
1,6 |
|
5 |
GND |
Blue |
Green |
5 |
|
6 |
REC |
Green |
N/C |
|
|
7 |
REMOTE |
Brown |
White |
8 |
|
8 |
DET OUT |
Grey |
Grey |
7 |
|
9 |
S METER |
Orange |
N/C |
|
|
10 |
GND |
Violet (Purple) |
N/C |
|
|
Frame |
GND |
Shield |
Shield |
Frame |
|
|
|
|
Black |
Unconnected |
|
AR8200 |
Use |
OS8200 |
HP600 |
HP600 |
|
1 |
+5V |
Red |
Yellow |
4 |
|
2 |
TXD |
White |
Orange |
3 |
|
3 |
RXD |
Black |
Red |
2 |
|
4 |
GND |
Yellow |
Blue/brown |
1,6 |
|
5 |
AGC SWITCH |
Blue |
Green |
5 |
|
6 |
REC |
Green |
N/C |
|
|
7 |
REMOTE |
Brown |
White |
8 |
|
8 |
DET OUT |
Grey |
Grey |
7 |
|
9 |
S METER |
Orange |
N/C |
|
|
10 |
AGC |
Violet (Purple) |
N/C |
|
|
Frame |
GND |
Shield |
Shield |
Frame |
|
|
|
|
Black |
Unconnected |
Signals description:
| N/C | No connection |
| +5V | Internal DC-DC converter output |
| RXD and TXD | RS232 comm on TTL levels, both through internal 1k resistors to CPU |
| REMOTE | Two state output, low switching recorder on (squelch is open). 1k resistor |
| REC | Audio output for optional recorder, AC-coupled with 100n capacitor |
| DET OUT | Direct output from narrowband FM detector through 1k resistor, not AC-coupled |
| S METER | Signal level, beware, connected to CPU A/D input ! |
| GND | All grounds in connector are connected together |
From Service Manual AR8200MK2 addendum
(downloadable at AOR UK):
The AGC output gives a DC voltage level which reduces with respect to input signal level increase.
The 'S' meter (previously labeled AGC) output increases with signal level.
The 'AGC Switch' is a 4V level which if grounded will disconnect the internaly produced AGC level allowing it to fall to 0V (i.e. giving a large level of attenuation). This also allows an external AGC signal to be fed to the set via the AUX AGC connection above.
Note: the detector output is available only in NFM and SFM receive mode!
Interface construction details
Schematic diagram:
I leaved here only universal interface design powered from PC serial port, because this version is usable with any equipment with need of signal levels converting between RS232 and TTL.
Component placing and PCB pictures of interface:
Construction notes:
- PCB's are designed as one layer, dimensions 39 x 15 mm.
-On component placing pictures is top conductive layer marked red, blue is bottom layer (make only wire bridges).
- Holes for wire bridges are idealy 0.6 mm, for LED's may be 0.8 mm. Make bridges on bottom side (where are not conductive layer) with tinned wire 0.5 mm of diameter.
- MAX232 chips (or other 232 clones) are available in two versions with wide or narrow package. PCB's are designed for narrow packages.
- You can use MAX202 (or other 202 clone), then use 100nF capacitors instead 1uF.
- If you want to use interface wih discriminator output, connect wires directly to connector pins 7 and 6.
- Standard version of voltage regulator (7805) can be used instead of SMD (SOT-89) version. Simply cut legs to adequate lenght and solder it with marking on top.
- If you make PCB with photoresist, take care with right orientation.
IMPORTANT NOTE:
If you already have one of early interfaces and plan
to using it with latest AR8200MK2, you must cut ground trace at pin 5 of X2
connector, leave it unconnected and reconnect ground trace to pin 1 (6) of same
connector. Reason is in change of pins assigment in scanner AUX connector and
with early design interface, you connect AGC control to ground, resulting in no
RF signal received during connection via cable.
IMPORTANT NOTE II:
If you using this interface with HP600 cable on
AR8200MK2 later models, you must isolate pin number 10 on AUX (AR's) connector,
because is internaly in connector housing connected to shield and ground. This
cause grounding of AGC Control signal and imposible receiving when cable is
plugged. Fix is simple. Cut a piece of self adhesive tape about 15 mm long and 2
mm wide. Put this into cable AUX connector and stick on last two pins to isolate
them. Remaining tape attach onto connector's outer metal frame.
Pictures of assembled interface with discriminator output:
