Model T Serial Cable: Difference between revisions

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==Summary==
==Summary==
The ideal cable to go from a PC to a Model 100, 102, 200, or 600, is "9F/25M serial null-modem full-handshake".
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.
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. There is some suggestion that maybe this is actually the original standard, and IBM came along later and changed it by putting male connectors on their PCs, but in any event, 25pin DTE ports being male has been the universal standard now for decades.
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.
*Any modem or printer or digital scale or any other kind of peripheral with a serial connection will be wired DCE with a female connector, usually 25 pin.
*Any serial port card or usb serial adapter for a PC will be wired DTE with a male connector, usually 9 pin.


That means that usually you always need some kind of adapter between a PC and a M100/102/200/600.
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 fo wiring and connectors.


The easiest way to connect with parts you are most likely to already have lying around, is to use a [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 cables==
==Ideal cables==

Revision as of 05:37, 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 fo 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
No RI
DCD+DSR<-->DTR
S+PG
No RI
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

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