zben@umcp-cs.UUCP (10/19/83)
Wouldn't it be nice if everyone standardized on using FEMALE connectors for DCE equipment and MALE connectors for DTE equipment? That way, if you can physically make the connection, it will be electrically correct. In my experience nearly all equipment uses FEMALE connectors on fixed boxes and MALE connectors on cables. Imagine my delight upon finding my new H19 with a MALE (DTE) connection on the back. This also had the big win that the cable provided was MALE on one end and FEMALE on the other. Thus you could use this cable as an extension cord in a pinch. To my knowledge Heath is the only manufacturer to embrace this standard. Yesterday a friend told me his brand new U.S. Robotics Password modem sports a MALE DCE connector. Sigh. zben
andree@uokvax.UUCP (10/28/83)
#R:umcp-cs:-322000:uokvax:2000003:000:261 uokvax!andree Oct 25 20:55:00 1983 Sorry, but making the DTE hardware male and the DCE hardware female would NOT guarantee that things would be electrically correct. There are THREE different signals in the RS-232C that people have used to handshake with (DTR/DSR, CTS/RTS and CD (gag)). <mike
preece@uicsl.UUCP (11/03/83)
#R:umcp-cs:-322000:uicsl:4100002:000:765 uicsl!preece Nov 2 08:42:00 1983 I the discussion of the gender of the connector on the Password modem, which started this, it is described as having a cable with either a male or female connector (I haven't actually seen one). This seems perfectly reasonable if you consider it as giving you the choice of considering the cable to be either the modem itself or the connecting cable itself (designed to plug into the device attached to the modem). The person buying the Password for home use is likely to want to minimize costs. Cables are expensive. By giving you your choice of connector you can buy one suitable for plugging into a terminal or into a computer, depending on what you have (assuming the connector is appropriately wired for its sex) and avoid buying a separate connecting cable.
minow@decvax.UUCP (Martin Minow) (11/04/83)
One of the problems with RS232 gender is that many manufacturers do not understand how to build RS232 ports, and you can find all kinds of strange systems floating around. In my lab at work, we are blessed with an in-circuit emulator which needs a male-male null modem to connect it to the outside world. In fact, if I look around, I can also find female-female straight-through cables, too (female-female cables are usually null-modems). Even when you understand the problems, you may not be able to offer correct solutions. DECtalk has two terminal ports which connect to a host computer and a local terminal respectively. Since one port is a DTE (DECtalk is a terminal) and the other is a DCE (DECtalk is the host), we should have one male and one female connector. But the field-service people don't have a male data loopback connector for testing, so we have two male connectors and will ship a female-female null modem cable to simplify connection to a local terminal. Martin Minow decvax!minow
andree@uokvax.UUCP (11/09/83)
#R:umcp-cs:-322000:uokvax:2000005:000:529 uokvax!andree Oct 30 13:32:00 1983 You are correct: CD isn't a handshake line. I spent a rather long afternoon trying to figure out why my printer wasn't handshaking correctly. It wasn't until I tried the last resort (reading the manual) that I found out that they were using CD as a handshake, and ignoring the standard about what should/shouldn't be used for handshaking. My point was that getting manufacturers to agree on a gender for the plug is NOT sufficient to make things work. You have to get them to agree on what the standard actually says... <mike