Denis A. Paquette, Toronto, Ontario, on May 8, 1989, at 10:12pm.
This document was written with a mono-spaced font so that it could be used on non-proportional spaced programs. If you are reading this on a Macintosh, use [Monaco 9].
The information below comes with no guarantee, expressed or implied. This information is free and may be distributed around as widely as possible. I have tested the information below with a Macintosh SE/30 using version 6.0.3 software and an USRobotics Courier HST modem. I used ZTerm 0.75 as my communications software. I have tested the modem with this configuration and am very satisfied with the results.
I have also tested using this cable on an Apple IIgs with ProTERM using the software protocol, by changing the registers accordingly. Although this works properly, it doesn't supply you any benefit unless you have a comm program that supports the hardware handshaking. My hope, is that all comm programs, like ProTERM, will give you this option in the future. I haven't checked any other comm programs, so there may be some out there that support hardware handshaking and then this information will be of benefit.
*** Warning ***
Although I never exit my comm program without doing a proper ending of a BBS session, with this cable configuration, it is possible to leave the comm program without the modem hanging up. (Dropping DTR). This is because that signal is now being used for RTS. I have never depended on exiting my comm program to hang up the phone, because I always do it from the BBS's program. I don't think that anybody would do this, but I decided to post this warning just in case. In other words, do a proper end of session before exiting the comm program.
There is one benefit to not dropping DTR when exiting your program. You can go to the operating system level, perform some function, (ie. pack a file), return to your session that is still in progress and upload the packed file. Again, this shouldn't be a normal habit, (especially if you're paying for the call), but, it can get you out of a bind sometime. (This example will not work in ProTERM due to the Main Menu Window that always comes up, unless you use the null modem driver.)
My purpose for writing this text file, is to inform people of the fact that hardware handshaking through the Mini DIN 8 serial port on the Apple IIgs and the later Macintosh's is possible with the proper cable configuration. I hope that this information will be useful to everyone.
If your comm program supports hardware handshaking and you have constructed the cable described further on in this text file, you may set up the registers as shown below.
USRobotics Courier 9600 HST Settings....
C=1 E=1 F=1 M=1 Q=0 V=1 X=7 B=1
BAUD=19200 PARITY=N WORDLEN=8
DIAL=TONE ON HOOK TIMER
&A1 &B1 &G0 &H1 &I0 &K1
&M4 &N0 &P0 &R2 &S0 &Y1
S00=000 S01=000 S02=043 S03=013
S04=010 S05=008 S06=002 S07=030
S08=002 S09=006 S10=007 S11=070
S12=050 S13=000 S14=000 S15=000
S16=000 S17=000 S18=000 S19=000
S20=000 S21=010 S22=017 S23=019
If your comm program doesn't support hardware handshaking, then you will have to change &B1 to &B0, &H1 to &H2, &R2 to &R1.
*** Beware ***
Beware of the &I register. I had mine set to &I1 at first and found that my XModem transfers would freeze up part way through. I then decided to test it further by trying &I2. This caused the transfer to freeze sooner. Therefore, I would recommend that you always have it set to &I0 if you intend to use XModem. I did not experience this problem with any other protocol, but that doesn't mean that it can't happen. It just means that I haven't experienced it yet.
Courier HST 9600
DIP switch settings
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10
_________________________________________
| X X X X | UP (OFF)
| X X X X X X |
|_________________________________________| DOWN (ON)
(S1 is set to ignore DTR.)
(As you can see, the switch settings are all set to default.)
(QUAD switch is set to the up position as usual.)
Below is the cable configuration that I am using.
Cable Config
Apple IIgs/ RS/232
Mac Serial Port Modem Port
Mini DIN 8 Male 25 PIN Male
HSKO 1 ------------------------- 4 RTS
HSKI 2 ------------------------- 5 CTS
TX 3 ------------------------- 3 TX
GND 4 ------------------------- 7 GND
RX 5 ------------------------- 2 RX
--- 6 DSR
|
--- 20 DTR
Pin 6 to Pin 20 is not required for the Courier HST, but allows you to use it as a generic cable for any modem. You can then select [Hardware] or [XON/XOFF] handshaking in your terminal programs. Some programs, (like Red Rider for the Mac and ProTERM for the Apple II), do not give you the option of using Hardware handshaking. (At least at the time that I wrote this) If this is the case, don't forget to change the modem registers accordingly.
For the Apple IIgs, hopefully Greg Shaefer, who wrote ProTERM, will take notice of this and include hardware handshaking in future versions of his program.
I use ZTerm on the Mac and am very pleased with the results. I turned off the [XON/XOFF] options and turned on [HW Handshaking] in the Settings/Flow Control Menu. I set the baud rate to 19.2k. On my SE/30, I am able to keep up with 9600 baud YModem-G transfers with 98%+ efficiency without data compression turned on. (This is the rating at 9600 baud. ZTerm shows it as 49% due to the fact that it is comparing the efficiency at 19.2k. You must remember that you are really communicating at 9600 baud to the bell line and 19.2k from your comm program to the modem.) I have not yet tested it with file compression turned on, but you can expect better results in that mode, if the file you are transferring has not been compressed already. (ie. using a program like StuffIt) I highly recommend using ZTerm. It is well worth the $30 ShareWare fee. I hope that enough people will send David Alverson money to give him incentive on seeing this project to the finish. I also hope that comm programs in general, that don't support hardware handshaking will also take the cue. (Note: For Macintosh users, please refer to the [Flow Control] heading in the ZTerm Doc's.)
Below shows the configuration of a standard Mac/GS modem cable.
Config for stock Mac/GS cables
Apple IIgs/ RS/232
Mac Serial Port Modem Port
Mini DIN 8 Male 25 PIN Male
HSKO 1 ------------------------- 20 DTR
HSKI 2 ------------------------- 8 DCD
TX 3 ------------------------- 3 TX
GND 4 ------------------------- 7 GND
RX 5 ------------------------- 2 RX
If you want to, you can use the standard Mac/GS modem cable, buy a Jumper Box and make the following jumpers in the box. But, you better make sure that it is the above cable that you have. You must be very cautious when making the jumper box. I found that the pin numbers are backwards on one side of the board and they are correct on the other. I had to compare the pin number on the connector to the number on the board by following the connection. Also, the female side goes to the cable and the male side goes to the modem. If your in doubt, have someone with experience do it. If you have to pay to have it done, it will probably be cheaper to have the proper cable made up instead.
