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PowerBook Duo Wifi Modem

sutekh

Well-known member
Very helpful information @Trash80toHP_Mini and @Challenger 1983. Interesting question about the internal modem and whether or not if functions when docked. I don't see any reason it couldn't from a hardware standpoint, but would be very surprised if it's selectable when docked. I've been reticent to make any permanent mods to the Duo's board itself that can't be undone as easily as replacing an original module (I'm kind of a stickler for originality), but there are a lot of potential options to explore via the expansion connector if I abandon that principle.

 
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Challenger 1983

Well-known member
I agree with the idea of keeping the modem on the expansion board as like you said I prefer my machines to have reversibility and originality but I think with the tight integration that the duo’s are based around may make it difficult to preserve this originality   

 

Trash80toHP_Mini

NIGHT STALKER
Interesting question about the internal modem and whether or not if functions when docked.
When the Duo's Docked or MiniDocked, it's definitely the Duo's internal modem that's active via the Internal DAA relay/repeater/whatever thingie. I've mislaid my camera, but when I find it I'll post pics of the boards, it's certainly not a modem, but looks to have the oomph parts for driving the phone line from the data feed.

What's most interesting to me would be the state of the standard serial ports when the internal modem is in use. For the Quadra 630 and its offspring, when ComSlot Modem was standard equipment, there was a plug blocking the useless Modem port. You needed to remove the modem and plug a/o install the ComSlot NIC to get the use of the serial port back. Gotta hit the docs, curiouser and curiouser. :huh:

 

sutekh

Well-known member
@Trash80toHP_Mini Very interesting, thanks for posting! Just the DAA then. So using a dock's "modem" must seemingly require the internal modem? That would explain why there's a line in the above diagram going from the MUX to the expansion connector.

What would be the equivalent of the rockwell chip on this board?


@Challenger 1983 I believe the answer is that there isn't an equivalent. The pictured boards seemingly just contain the Digital Access Arrangement circuitry (step down x-former, signal conditioning, surge suppression, etc.).

Given that, the two biggest outstanding question I have are:

  1.  Whether modem communication is possible when docked via one of those modules pictured above, but without an internal modem? For instance, the crummy soft modems (often called winmodems) of the day were just DAAs with some port interface requiring the CPU and installed software to emulate the hardware.  Does the Duo potentially implement something similar?
  2.  Did Apple provide some sort of non-ASIC (Rockwell or otherwise) equipped basic module in place of the modem version with just power/reset buttons if a Duo was ordered without the internal modem? I've never seen such an animal, nor have I ever seen a Duo without an internal modem, but my experience with this platform is pretty limited. This passage is lifted directly from the Duo "Getting Started" manual, which strongly suggests that not all Duos shipped with internal modems: "Apple offers an optional, low-power, internal fax/data modem for your computer."
 
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Challenger 1983

Well-known member
@Trash80toHP_Mini Very interesting, thanks for posting! Just the DAA then. So using a dock's "modem" must seemingly require the internal modem? That would explain why there's a line in the above diagram going from the MUX to the expansion connector.

@Challenger 1983 I believe the answer is that there isn't an equivalent. The pictured boards seemingly just contain the Digital Access Arrangement circuitry (step down x-former, signal conditioning, surge suppression, etc.).

Given that, the two biggest outstanding question I have are:

  1.  Whether modem communication is possible when docked via one of those modules pictured above, but without an internal modem? For instance, the crummy soft modems (often called winmodems) of the day were just DAAs with some port interface requiring the CPU and installed software to emulate the hardware.  Does the Duo potentially implement something similar?
  2.  Did Apple provide some sort of non-ASIC (Rockwell or otherwise) equipped basic module in place of the modem version with just power/reset buttons if a Duo was ordered without the internal modem? I've never seen such an animal, nor have I ever seen a Duo without an internal modem, but my experience with this platform is pretty limited. This passage is lifted directly from the Duo "Getting Started" manual, which strongly suggests that not all Duos shipped with internal modems: "Apple offers an optional, low-power, internal fax/data modem for your computer."
So essentially the Modem board just handles the step down and conversion from 48vAC, I’ll look through the developer notes some more and see if i can find an answer as to how the modem is operated when the Duo is docked.

 

Trash80toHP_Mini

NIGHT STALKER
I thought you guys'd get a kick out of that pic.

I'm guessing the Modem uses the (missing) serial port of the 2300c and that it probably ties up the Modem port of the DuoDock and MiniDock, though I don't know from experience.*** That'd be the way things worked in the Performa era, Apple plugged up the Modem port connector on models with a ComSlot Modem. Who knows? The Dock and MiniDock are multi-function PDS expansion cards at Slot $E IIRC. Anything could go in such a setup, much did.

As I'd said, these are the only Modem specific lines I found on the Docking Connector:

143____ DAA CNTLF___Modem DAA control
144____ DAA ID IN_____ID input from 152-pin connector to Modem card
145____ /RING DET____Ring detect signal from the modem DAA
146____/RB DVR_______Modem relay B driver
147____/RA DVR_______Modem relay A driver

Are th0se enough to connect between the Duo's "Internal Modem" and the Dock/DAA board? Ports-n-Pinouts has these Duos labeled Modem or Printer, on the 2300c it's Serial Port.

Duo-n-Dock-ports.JPG

*** I had a much faster portable external in my bag that had all the PowerBook specific bits I needed when the same package came out in a faster version for PC. Beautiful little Charcoal things. I only ever really used the internal Modem to FAX AI layouts out on one of a customer's lines back to myself on the LaserPrinter FAX machine line in his office for markup, then edit and back around again. Took about 35 iterations to finalize THE most notoriously confusing Parking Lot Rate Sign in the Big Apple. The Times made it a poster girl, but she was well within the letter of the law, they should have printed a picture of one that broke one. [:D]

 

sutekh

Well-known member
I had a bit of a eureka moment on this topic yesterday. I stumbled across a more generalized "Macintosh Duo System" Developer Note that I hadn't encountered before on other sites:


Remarkably, chapter 5, Internal Modem, includes nearly all of the detail so glaringly absent from the 280c's specific Note and answers many of the questions posed above. Here are a few highlights:
 

  • As theorized, the internal modem including the Rockwell "data pump" is absolutely required for docked modem communications. Duo Dock and MiniDock only provide the DAA via the pins on the 152-pin connector you've identified above @Trash80toHP_Mini (see Fig. 5-6 & 5-7)
     
  • Per the following, it sounds like there is indeed a software abstraction layer included in the Express Modem driver which is what I suspect I was interfacing with above:


    Many of the modem and fax functions are implemented in software running on the PowerBook Duo’s operating system. This allows easy field upgrades, and reduces hardware costs. This type of architecture also makes it easier to add new features to the modem.
     

[*]There's a partial pinout of the modem's 50-pin connector beginning on pg.58. Unfortunately it only seems to cover power and analog signaling  :/  What the other 25 pins do remains a mystery...
 



So here's where I think that leaves me: Working with or bypassing the Express Modem software layer and split-serial architecture isn't in my wheelhouse. But, I have a glimmer of hope... The 280c's Developer Note includes the following two passages:
 

  • When describing the GetIntModemInfo routine on pg.58, the following condition is included: "Modem is a serial modem" among other options pertaining to Express modem installation
  • Pg.29 includes the following: "If you have a third-party internal modem installed, the control titles will be Internal Modem and External Modem"
     

Whether on not a 3rd party serial modem was ever offered for the Duo platform, I can't say (there's certainly no hint of it on today's internet), but it seems clear to me that Apple at least included hardware and software provisions for such a device. I wouldn't be at all surprised if one or more of those undocumented pins on the 50-pin header included a modem ID pin signalling the software how to behave. E.g., Pin X grounded, Express modem installed, software modem emulation enabled, CTB and PB Setup CDEV options updated accordingly. Pin Y grounded, serial modem installed, PB Setup CDEV options default to traditional Internal / External options. That's how the PB 1xx does it FWIW (pin 15 to GND = modem inserted, pin 16 low = serial modem).

I'm not about to start randomly grounding pins, but neither have I given up hope that there's a way to make this work...

 
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sutekh

Well-known member
Any updates on this?
With year-end at work and holidays at home, I haven't touched my Duo since posting the above I'm afraid. I'm hoping to find some time after Christmas to pursue the theory outlined above pertaining to the possibility of a built-in concession for a 3rd party traditional serial modem. I really with the Duo Developer's Note was more complete in that area. More than 2/3rds of the modem board's 50 pins are undocumented, some of which are clearly connected to the RCV144DPL "data pump".

 

Trash80toHP_Mini

NIGHT STALKER
Third party internal modems go all the way back to the faster than Apple's internal I got from APS along with max RAM upgrade and nice big little HDD for my first laptop love, a spankin' new PowerBook 100.

More than 2/3rds of the modem board's 50 pins are undocumented, some of which are clearly connected to the RCV144DPL "data pump".


Doesn't surprise me at all, the modem board's the size of a PCMCIA card's PCB, no telling what they planned?

https://pdf1.alldatasheet.com/datasheet-pdf/view/167236/CONEXANT/RC144LD.html

I wonder where any lines that don't head to that data pump wind up? The hole in the back for the modem has the entire surround of the RJ-11 jack sticking out. Plenty of room for an RJ-45 jack sitting just a bit farther back. Someone made an EtherNet MicroDock after all. Curiouser and curiouser. [:)]

 

sutekh

Well-known member
Third party internal modems go all the way back to the faster than Apple's internal I got from APS along with max RAM upgrade and nice big little HDD for my first laptop love, a spankin' new PowerBook 100.
  
Sure, but were there any 3rd party serial modems offered for the Duo? Aside from those few obscure references that suggest the potential of such a device the Developer's Note, I've found no reference anywhere to confirm such a thing ever existed (although I'm certainly hoping it did, or was at least planned for).

Doesn't surprise me at all, the modem board's the size of a PCMCIA card's PCB, no telling what they planned?

https://pdf1.alldatasheet.com/datasheet-pdf/view/167236/CONEXANT/RC144LD.html


At least in the case of my two modem boards (I can't confirm they're all the same since the PB 1xx's certainly aren't) the "data pump" in question is the DPL variant covered under this datasheet: https://www.datasheets360.com/pdf/2794983860166016737.

It's helpful to be sure, but doesn't indicate anything Apple / Duo specific of course. What I'm theorizing is that if the Duo architecture included a provision for a traditional serial modem (again, those references in the dev note...) then something would need to signal to the Duo what type of modem is installed! As mentioned in a previous post, on the PB1xx series, that a modem is installed and of what type is indicated by grounding certain pins on the connector. No great way to know if / how something similar exists for the Duo without a full pinout of the 50-pin connector unfortunately.

If I want to move forward, I'm probably going to have to spend some quality bench time with my scope and logic analyzer in an attempt to reverse engineer what the missing pins--especially any that don't terminate at the Rockwell--might be responsible for.
 

Someone made an EtherNet MicroDock after all. Curiouser and curiouser. [:)]


The Newer Technology Ethernet Microdock, while certainly awesome, is a bit less puzzling IMO, as the 152-pin PDS connector includes a complete SCSI pinout. That particular device is just a SCSI NIC with clever packaging. I happen to own one, and the driver allows you to set its own SCSI ID and everything :)

 

Trash80toHP_Mini

NIGHT STALKER
I don't see any reason Apple would have bothered with a serial modem, they never updated the 14.4 modem they had from the start did they? There were much better portable modems on the Market, I should look for mine and post a pic, perfect down to styling and PowerBook Duo Charcoal plastics.

The Newer Technology Ethernet Microdock, while certainly awesome, is a bit less puzzling IMO, as the 152-pin PDS connector includes a complete SCSI pinout.


Check that Docking connector pinout again, it's a bridged 68030 PDS with some housekeeping signals like ADB, Modem DAA control lines and such. Duo system requires a SCSI MicroDock or MiniDock with the SCSI/SCC Combo chip for external SCSI. Take a look inside that Newer MicroDock I'm so jealous of, I'll bet a shiny nickel you won't find a SCSI interface setup, it'll be an 030 PDS NIC. [:)]

edit: https://pinouts.ru/Slots/duodock_pinout.shtml

 
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Trash80toHP_Mini

NIGHT STALKER
When you're buzzing connections on the Modem slot, check the unknowns against the PBX bridge chip's legs and PDS connector pins while you're at it. Just how many Address/Data/Control lines would it take to put 10bT on that Power Board/Modem connector?

The Duo System was Apple's pride and joy for a time after release, but after they goofed up and promised a PPC Upgrade path they really just wanted it to die on the vine, fall off and blow away. Promise kept, the 2300c is cool beans in several varieties. :approve:

 

sutekh

Well-known member
I don't see any reason Apple would have bothered with a serial modem, they never updated the 14.4 modem they had from the start did they?
I think perhaps you keep missing my point here :) I don't believe they did or frankly even care if APPLE released such a device, only that they included a provision for one. Whether a 3rd party (e.g., Global Village, et. al) ever did is a question I haven't been able to answer though.

Take a look inside that Newer MicroDock I'm so jealous of, I'll bet a shiny nickel you won't find a SCSI interface setup, it'll be an 030 PDS NIC. [:)]


The housing is glued together, and given rarity / cost, I'm not anxious to force it open, but unnecessary regardless. You're absolutely right. What I remembered being a SCSI ID config in the driver CDEV is in fact a PDS slot assignment. The selectable options are 1-6, which I incorrectly assumed without looking more closely were available SCSI IDs knowing my HD is on ID 0 and 7 is reserved for the controller. Looks like Newer Technology just leveraged a common driver for their various NICs, including both PDS slot EtherNICs and this microdock.

 

sutekh

Well-known member
Sorry to sounds like a broken record on this and the battery, but no. Been slammed with too many other priorities. Hoping to spend some time on it this weekend. It's a long-shot, but based on that hint from the dev note, I'm still hoping there might be a way to signal to the Duo that a serial modem is installed and bypass the software Hayes emulation layer. The guts of my poor 280c are strewn about my office, taunting me, judging me for my indifference and inaction. It's time to wrap it up I suppose...

 
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