Serial port confusion.

[skullandbones]

Actually, Sinclair's solution was a good idea of having a DTE and a DCE configured serial port because it avoids having an external NULL modem gender changer because the conversion is builtin to the QL.

In the 1980s and early 1990s, if you were not using a 25 pin D type then your solution was proprietary. As there was no official standard for minimal "RS-232" then you had to gamble on being compatible with 3rd party equipment. So providing a DTE and a DCE increased the chances of being compatible with other people's equipment.

[Dave]

Who remembers which is which, though? And since the RX side is really one port….

[Derek_Stewart]

Hi,

If the QTPI Manual is consulted, there is complete section on QL Serial port connections.

The SER2 connections:

Code: Select all

SER2     DB9
1. GND    5. GND
2. TxD    3. TxD
3. RxD    2. RxD
4. DTR    7. RTS
5. CTS    8. CTS
6. NC

Works for a Hayes compatible modem and a Serial Mouse.

For connection to SER1, the TxD,RxD and DTR,CTS are reversed:

The SER1 connections:

Code: Select all

SER2     DB9
1. GND    5. GND
2. RxD    3. TxD
3. TxD    2. RxD
4. CTS    7. RTS
5. DTR    8. CTS
6. NC

I have not tested yet.

[t0nyt]

Hi,

All sorted now, I forgot all about comms cable.

But looking at the QTPI documentation this defines what is required

Code: Select all

SER2     DB9
1. GND    5. GND
2. TxD    3. TxD
3. RxD    2. RxD
4. DTR    7. RTS
5. CTS    8. CTS
6. NC

note QL Pin 4 is actually a RTS rather than a DTR.

I connected this cable from a Trump Card QL with 8049 to Simulant Wifi Modem, which worked after setting Hayes register S54=2 which is DTR high.

Next step replace 8049 with Hermes.

Is this pinout definitive for connecting a Hayes compatible modem please?

My existing adapter (not been used for anything yet) has the pinout in the image below, which suggests I'll need to re-route the pin 4 from D9 pin 4 to pin 7?

IMG_3748.PNG (142.25 KiB) Viewed 3894 times

Many thanks

[t0nyt]

Hi,

All sorted now, I forgot all about comms cable.

But looking at the QTPI documentation this defines what is required

Code: Select all

SER2     DB9
1. GND    5. GND
2. TxD    3. TxD
3. RxD    2. RxD
4. DTR    7. RTS
5. CTS    8. CTS
6. NC

note QL Pin 4 is actually a RTS rather than a DTR.

I connected this cable from a Trump Card QL with 8049 to Simulant Wifi Modem, which worked after setting Hayes register S54=2 which is DTR high.

Next step replace 8049 with Hermes.

Is this pinout definitive for connecting a Hayes compatible modem please?

My existing adapter (not been used for anything yet) has the pinout in the image below, which suggests I'll need to re-route the pin 4 from D9 pin 4 to pin 7?


IMG_3748.PNG


Many thanks

I've purchased and wired up a terminal type D9 as per Derek's layout as a starting point, have opted for the terminal type so I can change the cable layout without a soldering iron!

Everywhere I look I see different pinouts for SER2 (Dilwyn's site seems to say Modem should be on SER1 which adds more confusion for me)

The only thing that seems consistent over all sources I've found is Pin 6 and Pin 1

Will try the cable I've made when modem arrives

[Dave]

Actually, Sinclair's solution was a good idea of having a DTE and a DCE configured serial port because it avoids having an external NULL modem gender changer because the conversion is builtin to the QL.

They made up for it with the bad idea that received information from both sockets goes to a single port on the 8049, which is passed to the 8302 over a single wire serial connection that is slower than baud rates you can set in BASIC.

[Derek_Stewart]

The wiring diagram, detailed above works perfectly with SER2 and the Simulant WIFI Mode,, for SER1 an interchange of the contol lines is required.

I thought about having a switchable serial cable to switch between SER1/2, I have get a proto-type made.

A simple cable from QIMSI SER3 would also work.

[t0nyt]

The wiring diagram, detailed above works perfectly with SER2 and the Simulant WIFI Mode,, for SER1 an interchange of the contol lines is required.

I thought about having a switchable serial cable to switch between SER1/2, I have get a proto-type made.

A simple cable from QIMSI SER3 would also work.

Hi Derek,

I ended up using the one I already had (as per the image) and it works fine with my WiFi modem (not had a single error as yet, but I only need it running at 1200 to get the time on each boot currently)

[Derek_Stewart]

Hi,

You can set the Baud rate of the serial port to the maximum, using the S*Basic BAUD command, then set the Modem Baud Rate to the maximum the modem supports and can connect from the BBS.