Hello ALL, I found many peoples these days throw away or sale for pennies their old ROCKWELL dial-up modems. Also, I found that typical rockwell modem hardware contains uart + cpu + rom + ram and phone line interface. It is easy task to download and upload own firmware into modem's flash. But, I can not find any related firmware sources, tutorials nor information about internal registers and onchip peripherals. Does anyone know anything about rockwell modem firmware programming?

Update:
these are examples of harware I'm talking about:
older: GVC model SF-1156V/R1
internal chips: RP56D/SP R6764-61 and L2800-38 ram: issi is61c1024-15j flash: sst 39sf020 (also atmel 24c02n)
newer:
DLINK model: DFM-562E/SG
internal chips: CX06827-11 and 20437-11 ram:IDT71024S flash:at49f002nt (also includes atmel 24c02n)
ACORP model: M56SCD
internal chips: CX06827-11 and 20437-31 ram:lyontek ly611024jn-15 flash:eon en29f002ant-70pc (also ht24c02n)

Do you have a photo of the board with the chip IDs visible? And a model number for the modem?

Cheers
Ed

I have the 1987 Rockwell Modem Products Data Book here (3/4" thick) which also has an applications notes section. It does not seem to have enough 65-family content to send it to Mike to have him scan it and post on this website, but maybe someone can do that kind of thing. I would like to get it back in good shape though when they're done.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

From what I recall, and it's been a while, a Rockwell chipset modem consists of a CPU (C19 or derivative such as the C29 or C39), some sort of DSP (which I never had information on, it was always just a binary blob and a handful of tuning parameters), a standard ROM or FlashROM (the [234][79]x0[12]0 one or two megabit parts), RAM, and a bunch of other hardware. Older (before about '99, IIRC, and definitely before they started shipping USB modems) Zoom modems were Rockwell chipset (then they transitioned to a Lucent chipset which was based on the Z180).

Digging through my old parts bin, I find a 16-bit ISA 33.6k faxmodem with a 27C010 (one megabit PROM, not erasable) and a PLCC-68 marked "RC336ACFA", "R6749-25", "(C)ROCKWELL 96", "9734 B31463-3", "MEXICO". Looks like the CPU, DSP, and whatever else is on a single chip here. I also find an 8-bit ISA modem of some sort that has two PLCC sockets on it, but which has had all of the socketed chips removed and subsequently misplaced. I would hesitate to power these things up, as I've used them for soldering practice and mined them for parts at various times.