Re: A couple //c Serial Questions

[dempson@actrix.gen.nz (David Empson)]

Rubywand <rubywand@swbell.net> wrote:

> To clear up a few possible gaps and glitches in our telecom FAQs
> ... 
> 
> 
> 1. Is this the correct plug type and pin numbering for a cable connector
> intended for plugging into the //c serial port?
> 
> 
>    Mini-Din 5
> //c Serial Cable
>   (Male) Plug 
> 
>       |_| 
>    1       5
>     2     4
>        3

Yes (this is the plug, as you indicate).

> 2. The connection shown below does not seem correct. Will it work as a
> //c modem cable (supposedly to a modem with a DB9 connector or to a
> modem using a DB9-->DB25 cable)?
> 
> 
> DB9 Connector     5-pin male DIN Connector
> -------------     -------------------
> 
>     N/C            1 Handshake Out
>   3 TXD            2 Data Out (TxD)
>   5 GND            3 Ground
>   2 RXD            4 Data In (RxD)
>   4 DTR            5 Handshake In

The DTR pin is an input to the modem, so this is wrong.

> Is this better ...
> 
> DB9 Connector     5-pin male DIN Connector
> -------------     -------------------
> 
>   4 DTR            1 Handshake Out
>   3 TXD            2 Data Out (TxD)
>   5 GND            3 Ground
>   2 RXD            4 Data In (RxD)
>   6 DSR            5 Handshake In

Yes, except that this won't give you hardware handshaking.

To get hardware handshaking, replace pins 4 and 6 on the modem end with
pins 7 (RTS) and 8 (CTS) respectively.

Note that you need comms software which supports hardware handshaking on
the IIc to support this properly.  I expect ProTerm does, but Z-Link and
TIC almost certainly don't.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand