ITEM: AS8642L
RISCAWhat are the options to support a RS-449 port on an RS/6000?
Question: What are the options are available for running a RS-449 port
on an RS/6000?
What are my options? The port must conform to the EIA-449 physical
interface (DB-37) standard and the EIA RS-422 signaling standard. Only
one port is needed to meet the requirement.
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Response:
There are some ways we might be able to do this directly with a
RISC/6000. I got most of this information from the ARTIC developers in
Boca Raton, Florida. If you need further clarification or more detailed
information (such as pinouts), please contact them directly. In the
U.S., call 1-800-IBM-3333 and ask for "Artic160." In Canada, call
1-800-465-1234. Worldwide, call U.S. phone number 602-629-2505.
(I'm not sure about others) may also refer to their web site:
http://wwprodsoln.bocaraton.ibm.com
As RS-449 isn't a widely known standard, I'll define it first.
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WHAT IS EIA-449?
This standard was created in 1977 when what is now the EIA determined
that a complete communication interface required more than 25 pins. They
planned to phase out the 25-pin D-shell connector interfaces and replace
them with a 37-pin "primary" interface and a 9-pin "secondary" interface
standard, which they called RS-449.
Unfortunately, the larger connectors never really caught on so the
EIA published EIA-530 (basically a 5 volt version of the old RS-232, now
EIA-232, standard) in 1987. The Forward of EIA-530 standard indicates
that it is intended to "gradually replace EIA-449 for the higher data
rates." The document's Appendix also shows how to wire an EIA-530
25-pin connection to a subset of the 37-pin EIA-449.
ASSUMPTIONS:
I'm assuming you need to connect to something (like a modem) that
provides a 37-pin D-shell EIA-449 connection. Keep in mind that the end
user's final solution would involve both hardware (adapter and cable)
and software (device driver) for the application.
It looks like we can provide the hardware part, but the user will
have to write their own software because we don't have any software
(like SNA, TCP/IP, or asynch) that utilizes this interface today. The
user will want to order the appropriate RISC/6000 "Software Developer's
Toolkit" (provided by the ARTIC adapter developers in Boca Raton,
Florida) to make this job easier. For information on the new ARTIC i960
adapter series (includes the new V.36 adapter) refer to IBM Announcement
letter 195-296, dated 10/10/95. There are similar toolkits for the
older Micro Channel adapters (such as the X.25 Interface CoProcessor
adapter) and the ISA bus adapters.
EIA-499 ON THE RISC/6000?
The basic EIA-449 interface is the same as CCITT V.36. We offer two
ARTIC i960 V.36 solutions. The Artic960 CoProcessor 6-port V.36 adapter
and cable (in the 10/10/95 announcement letter) and the 4-Port Multi-
Interface AIB cables. This offers a possible off-the-shelf solution
providing the end user's equipment doesn't need any of the "special
function" signals and it can handle the EIA-423-A (single ended) control
signals. (The V.36 AIB implementation supports only EIA-422-A on the
data and clock lines, same as the V.35 interface on the X.25 Interface
Coprocessor. The AIB does support the DTE-sourced Transmit Clock.)
OTHER POSSIBLE SOLUTIONS:
Depending on which signals the user needs to support, there's also a
good possibility that any of our ARTIC RS-422 can be converted to the
EIA-449 pinout as described in the standard. One such alternative is
the 4-Port Multi-Interface AIB for the ARTIC960, which supports EIA-530.
The X.25 Interface Coprocessor Adapters (ISA or Micro Channel) would
be more cost effective for a single port with its V.35 mode, though it
supports the control signals in EIA-423-A (unbalanced 5V) mode versus
EIA-422-A (balanced 5V - 2 lines per signal) used in EIA-449. This isn't
normally a problem since these are low speed signals and the other line
can be grounded. You'd have to wire a special cable because V.35
specifies the rectangular M/34 (34-pin) connector.
All of this assumes the equipment you are connecting to does not
require the special function signals that do not translate back to one
of the other interfaces.
The signals that can be supported are:
Shield
Signal Ground
TxD Transmit Data
RxD Receive Data
RTS Request to Send *
CTS Clear to Send *
DTR Data Terminal Ready *
DSR Data Set Ready (Data Mode) *
CD Carrier Detect (Receiver Ready) *
TxCLK Transmit Clock (DCE source)
TxCLK Transmit Clock (DTE source) **
RxCLK Receive Clock
* EIA-423-A (unbalanced) signals on X.25 Interface Coprocessor
** Not supported on X.25 Interface Coprocessor
Support Line: RISCAWhat are the options to support a RS-449 port on an RS/6000? ITEM: AS8642L
Dated: April 1996 Category: N/A
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