ISDN Surfer

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ISDN Surfer is a Zorro card for "big box" Amigas that makes a direct connection to the ISDN-S0 bus.

With the availability of broadband internet connections we see the ISDN-Surfer as a backup, in case the broadband connection does not work temporarily. It's also an inexpensive way to add a clockport to a Zorro-machine. After our remaining stock has been sold, this product will not be produced any more.

With the ISDN-Surfer, you enter the information highway the digial way, because an ISDN board allows the direct connection to your phone company's NTBA. There is no key telephone system, no modem and no terminal-adapter in the way to reduce performance. The connection is purely digital, your Amiga is directly connected to the telephone switch in your phone company's premises!

The only requirement is an ISDN phone line, that is offered by many phone companies all over Europe. All these products have one thing in common: The NTBA, the interface for digital communication devices. You can connect a digital phone, a key phone system, or a computer to it. You don't have to worry about compatibility at all: Due to the drivers being totally CE96 (Q931) compliant, we can guarantee the function in practically every European country. Even the ISDN lines of American phone companies that use an S0-NTBA are supported.

Although ISDN technology is totally different from analog modems, you won't have any problems getting familiar with it's use, because the drivers emulate a Hayes-compatible modem with an AT-command set. This enables virtually any software that can handle a modem also to go online with the ISDN Surfer (only exception: Fax-software). Special commands in the set let you use the ISDN-specific services that your phone company provides. As the most popular example, the caller identification is to mention.

This means for you: With some quick changes in the settings of the software, you can adjust your TCP/IP stack to make use of the ISDN Surfer, no matter if you are using Miami, MiamiDX, AmiTCP or Genesis. After these small changes, you can go online with 64KBit. You can even make two independant connections at a time, just like having two separate modems or terminal adapters. Your Amiga can be connected to the internet while taking another call on the other line with an answering-machine-software for example. Naturally, the ISDN Surfer only occupies only the number of channels that it really needs, leaving the bus free for other ISDN devices at the same time. This enables you to surf the net and make a call at the same time - the most popular reason for getting an ISDN line. It does not make a difference what type of telephone you use: A digital phone, an analog phone connected to a key phone system, or an analog phone connected to an A/B adapter.

The ISDN Surfer has two expansion ports: One clockport as known from the Buddha Flash and X-Surf Ethernet boards, and one 26-pin expansion port. The clockport can be used to connect a Silversurfer serial port, or a Delfina Soundcard. The 26-pin expansion port can be used for a VarIO IO card.

The structure of the drivers is an added value for programmers: The driver understands Capi 2.0 commands as known from other platforms, so porting existing ISDN software will be an easy game, and writing new programs that make use of the ISDN Surfer is supported by some example sources written in C.

expansion ports

ISDN surfer has one clockport for A1200 expansions like Silversurfer and Delfina. Further, the 26-pin expansion port can be used for a Silversurfer "limited edition".

A third expansion port was meant for the telephone module, which was never released.

hardware details

Vendor ID: 4626 ($1212)

Product ID: 5 ($05)

Serial ID: 0

The autoconfiguration is optimized to fit in a single MACH110. One drawback had to be taken in order to make the design fit: The ISDN surfer can only be mapped to addresses in the regular IO area. That means, if the IO area is filled with other cards, the card will not work. However, this only happens if the ISDN surfer is the 8th card in your system that uses IO address space at $ex0000. This hardly happens, and if it does, a simple change of the board order will make the system work.

The data bus is buffered, meaning, the board should work in all known Zorro- setups. The bus design has been optimized for working with bad or even missing clock signals, so it should even work in RBM-towered 1200s. Another enhancement over the ISDN Blaster is the S0 bus part, that one is now symmetrical (as recommended by Siemens), and it uses a VAC ISDN transformer. VAC is a Siemens daughter, they guarantee to meet all the requirements of the used chipset.

low-level programming description

All addresses are byte-addresses. The whole board only uses even addresses. Do not use word-accesses to the board, because they may harm future options.

$0000-$00fa Configuration nibbles

The board does not only say that it supports shutup_forever, it really supports this feature. Although it is not used in normal configurations, it is implemented here. Usually, you don't use the airbag of your car every day, but you want to know that it's there!

$00fc IRQ lock register

A write to this register locks the IRQ selection. Once the IRQ is locked, the write-accesses to $00fe and $0240 do not have any effect. The lock can only be removed with a hardware reset. It is recommended to use the lock option, because there has been a lot of software that plays around with hardware registers. Intentionally or not - it could stop the product from working properly. Locking makes the hardware more stable, and more convenient for the customer (because there are no jumpers on the baord).

$00fe IRQ select register

A read from this register tells you which IRQ has been selected: If the MSB of this byte is set, the ISDN surfer uses IRQ6. If the MSB is 0, IRQ2 is used. This is useful for cross-checking if the lock-access has been successful. A write to this register selects IRQ2, no matter what value you write.

$0100-$01fe Siemens ISAC-S

Chip registers as described in the datasheet.

$0200-$02fe IRQ control, continued

after a reset, IRQ6 is selected. If IRQ2 has been selected by writing to register $00fe, it can be switched back to IRQ6 with a write to $0240.

$0200 read: Test access reset (hardware testmode only)
$0200 write: Test set access 0 (hardware testmode only)
$0220 write: Test set access 1 (hardware testmode only)

$0300-$03fe Siemens HSCX

Chip registers as described in the datasheet.

$0400-$7ffe mirrors

do not access, reserved for future use.

$8000-$9ffe clock-port

Clock port registers use the spare_CS signal only.

$a000-$bffe 26-pin expansion port

See low-level programming documentation of Silversurfer for details.

hardware test mode

jumper for hardware test mode

The Siemens ISAC-S and HSCX chipset was used on other ISDN cards as well. Should you want to use other ISDN software with ISDN surfer, you must be the legal owner of that software. Activate the hardware test mode by placing a jumper on the ISDN surfer as shown in the picture on the right.

Table of testmodes:

mode bit 0 mode bit 1 vendor/product ID
0 0 2189/3
1 0 5000/1
0 1 2092/64
1 1 5001/1

For every test mode, the memory map of the card with the corresponding vendor/product ID will be replicated. The original ISDN Surfer memory map will not apply any more. Further, a few distinct changes were made in order to keep the card from working with VMC software using this testmode. Only the BSD drivers for VMC cards, which are not copyrighted by Mr. Frank, will work using the testmode hack.

The testmode bits are NOT reset with a hard-reset, so the desired mode stays in the MACH chip after a warm start. Since the only reset to these registers is the read from $0200, the combination is undefined after a cold start. The modebits are locked with the IRQlock access, so once the IRQ is locked, the mode bits cannot be changed until the next reboot.

the 10-pin port for the telephone module can only be programmed via the Siemens Chipset, because it controls the IOM bus. The IOM bus is not directly mapped into the Amiga's address space. It wouldn't make any sense, because you wouldn't want a phone module that loads the CPU because it cannot talk to the ISDN chipset directly.


Capi20.device and isdnsurfer.device V1.938 (december 22nd, 2000): File:Isdnsurf.lha

isdnsurfer.device V1.944 (may 22nd, 2001) with support for Sync-PPP: File:Isdndev.lha

german User Manual

expansion port timing

ISDN Surfer IOR-timing
ISDN Surfer IOW-timing

Both expansion ports of the ISDN Surfer are driven by the same IOR/IOW timing as shown here. ISDN surfer and VarIO use the same timing.


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