Model T Serial Cable: Difference between revisions
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The easiest way to connect with parts you are most likely to already have lying around, is to use a common [https://www.cablewholesale.com/products/serial-modem-cable/at-modem-cables/product-10d1-02303.php 9F/25M Modem Cable] combined with a [https://www.monoprice.com/product?p_id=1203 9M/F Null-Modem Adapter]. | The easiest way to connect with parts you are most likely to already have lying around, is to use a common [https://www.cablewholesale.com/products/serial-modem-cable/at-modem-cables/product-10d1-02303.php 9F/25M Modem Cable] combined with a [https://www.monoprice.com/product?p_id=1203 9M/F Null-Modem Adapter]. | ||
==Ideal | ==Ideal Cables== | ||
These cables are wired null-modem, have all the connections for hardware flow-control, and the right connectors on both ends, all in one factory-molded piece. You don't need any null-modem adapters or gender-changer adapters. | These cables are wired null-modem, have all the connections for hardware flow-control, and the right connectors on both ends, all in one factory-molded piece. You don't need any null-modem adapters or gender-changer adapters. | ||
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:No RI | :No RI | ||
==Less | ==Less-Ideal Cables== | ||
These cables actually work fine for pretty much everything, including TPDD client/server connections, since there isn't even any way to *set* hardware flow control in either BASIC or TELCOM anyway. | These cables actually work fine for pretty much everything, including TPDD client/server connections, since there isn't even any way to *set* hardware flow control in either BASIC or TELCOM anyway. | ||
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:DTR<-->DCD+RTS+CTS | :DTR<-->DCD+RTS+CTS | ||
:No RI | :No RI | ||
==USB-Serial Adaters== | |||
Any one will work well enough. But some considerations are: | |||
Models based on FTDI chips are generally better than the ones based on Prolific chips. | |||
The serial cables all have screws in the plugs, so if you get a usb-serial adapter that has nuts (instead of screws) then the serial cable can be locked onto the usb-serial adapter with the screws. | |||
*[https://www.amazon.com/dp/B005SYQV9C Sabrent SBT-FTDI] | |||
Revision as of 06:19, 31 October 2017
Summary
The ideal cable to go from a PC to a Model 100, 102, 200, or 600, would be described as "9F/25M serial null-modem full-handshake".
That is an uncommon configuration to find in a single cable without needing adapters or needing to build it yourself custom.
The serial ports on Models 100-600 are wired DTE, the same as a com port on a PC, but with a female connector, unlike any pc.
This is a backwards configuration from everything else today. It has been suggested that maybe this is actually the original standard, and IBM came along later and changed it by putting male connectors on their PCs (probably to distinguish them from the printer port), but the standard today is that DTE ports are male. A female 25 pin port is either a parallel printer port or a DCE port on a modem.
That means that usually you always need some kind of adapter between a PC and a M100/102/200/600, because none of the normal cables you will have lying around will have the right combination of wiring and connectors.
The easiest way to connect with parts you are most likely to already have lying around, is to use a common 9F/25M Modem Cable combined with a 9M/F Null-Modem Adapter.
Ideal Cables
These cables are wired null-modem, have all the connections for hardware flow-control, and the right connectors on both ends, all in one factory-molded piece. You don't need any null-modem adapters or gender-changer adapters.
- DCD+DSR<-->DTR
- S+PG (Shield is also connected to pin 1 on the 25 pin connector, aka PG, Protective Ground)
- No RI
- Cable is thin. Good for portablity, but might mean the wires are thin and possibly not durable.
- DCD+DSR<-->DTR
- S+PG
- No RI
- Includes nuts (removable) on the 9-pin plug screws, so you can screw a usb-serial adapter together to the cable, no matter whether the usb-serial adapter has screws or nuts.
- No DCD
- No RI
Less-Ideal Cables
These cables actually work fine for pretty much everything, including TPDD client/server connections, since there isn't even any way to *set* hardware flow control in either BASIC or TELCOM anyway.
But the hardware in Models 100-600 *can* actually do RTS/CTS, if you manipulate the UART registers yourself from a machine language program. The only software I know of that does this is HTERM. So these cables are NOT suitable for HTERM
These cables are wired null-modem and have the right connectors all in one factory-molded piece also. They don't need any null-modem adapters or gender-changer adapters.
- DCD<-->RTS+CTS
- Unlike all others: RI<-->RI
- DCD<-->RTS+CTS
- No RI
- This "HP PLotter" cable is bizarre.
- DCD<-->RTS
- DSR+CTS<-->DTS
- No RI
- WTF??? HP are monsters.
- DCD<-->RTS+CTS
- No RI
- DTR<-->DCD+RTS+CTS
- No RI
USB-Serial Adaters
Any one will work well enough. But some considerations are:
Models based on FTDI chips are generally better than the ones based on Prolific chips.
The serial cables all have screws in the plugs, so if you get a usb-serial adapter that has nuts (instead of screws) then the serial cable can be locked onto the usb-serial adapter with the screws.