BBC Micro / Master Serial Communication with RM Nimbus PC-186

 

So far, I've successfully cracked Amstrad PC Serial Communication with Windows PC using Iomega ZIP-100 as external storage, adding 3.5" floppy drive on Amstrad PC Series, expanding my Serial / Parallel Data Communications Home Network, RM Nimbus PC-186 RS232 Serial Communication with Windows PC, RM Nimbus PC-186 RS422 Communication with Windows PC, Amstrad PCW Serial Communication with Windows PC and now I'm cracking "BBC Micro / Master Serial Communication with RM Nimbus PC-186" case

 

Before you can transfer files between BBC Micro / Master RS423 port to RM Nimbus RS422 (Aux or Piconet) port and visa versa via Serial communication, you must make up the serial cable for connecting both computers together, needing both a 5-pin DIN plug where the pins are in a “domino” arrangement (four pins making a square, with the fifth pin in the centre) & RJ11 6P6C Modular Jack Network Male Plugs, 6 Pin, Telephone Connector. In order to do that, here are the following pinouts for both computers:

BBC Micro / Master Series RS423 port pinouts	RM Nimbus PC-186 Series RS422 Aux or Piconet port pinouts

 
Make up a cable with the following connections:

BBC RS-423 Serial to RM Nimbus RS-422 AUX Serial Port cable connections

 

The finished product is similar to the one shown below. Luckily for me, I've purchased the very last Bespoke Item Order: AUX Serial Port to BBC RS-423 Serial port cable from Andy (cool-novelties) via eBay on Thursday 7th April 2022. 

 

AUX Serial Port to BBC RS-423 Serial port cable

After either way has done, insert the 5-pin DIN plug into 5 pin domino layout DIN RS-423 socket at the rear of BBC Micro so that the locating notch points to the RGB socket. It is physically possible to insert it the wrong way round and connect the other end of 6-way Bell Connector with the plastic catch on the top to AUX port on the back of RM Nimbus PC-186.

Next, switch on your RM Nimbus and insert MSDOS V.310 SYSTEM AND WELCOME DISK RELEASE 3.02A 4.11.85 into the disk drive (or log in as network manager if you have a Nimbus TN), allowing RM Nimbus to load automatic, pressing F9 to Quit Welcome program and type 'config' on the system prompt to load up CONFIG - see Chapter 7: The CONFIG Utility from page 66 or TD 3.9 (page 350) on Nimbus Owners Handbook, using CONFIG to set the AUX port to IO at 1200 baud as shown in 1st pic below.

 

For file transfer testing with between the BBC Micro and RM Nimbus, I've used RM 80x86 BBC BASIC for the RM Nimbus from RMNimbus BASIC - MDFS::Software.BBCBasic.RMNimbus web site and sending the TRANS.BAS file from RM Nimbus to the BBC Micro while leaving FILERECY.BBC file as it is on RM Nimbus with preparing BBC Micro to receive TRANS.BAS file from RM Nimbus by carefully typing the following (note that the character I is shift \ on the BBC micro):
 

*KEY1 NEW|M*FX7, 4|M*FX2,1|M<ENTER>

Then press the function key 1 (f1) on the BBC micro.

Send TRANS.BAS from MS-DOS on Nimbus by typing:

COPY TRANS. BAS COMB<ENTER>

When the transfer is shown to be complete by the Nimbus, press <BREAK> on the BBC micro, type OLD <RETURN> and save the program.

 

Since this transfer procedure didn't work very successfully, I've used Research Machines Kermit for 480Z & Nimbus (as shown in 2nd pic below) & Acorn BBC Micro Kermit 1.46 (as shown in 3rd pic below) from The New Open-Source Kermit Project - Historic Versions Area web site for both computers. Previously, I've used BBC PD Disk 007 - Acorn BBC Micro Kermit 1.45 from Index of /pub/unsorted/disks/Disk images/BBC PD Disc but ending up using Acorn BBC Micro Kermit 1.46 instead.

 

It works perfectly without any problems on both Kermit versions for data transfer exactly the same way in RM Nimbus PC-186 RS422 Communication with Windows PC except setting the speed to 1200 baud in Set/Show Parameters option on RM Nimbus via right arrow key until 1200 followed by RETURN key for acceptting new change, back to KERMIT MAIN MENU as shown in 2nd pic below. Next, select Connect to Mainframe, followed by F4 key, then press "K" to go back to KERMIT MAIN MENU and select Sending Files, then type TRANS.BAS (or type *.* to send all the files from disk) followed by RETURN key and finally type RECEIVE followed by RETURN key on BBC Micro side. Now, I know how use Kermit on Windows based PC, Amstrad PCW series, BBC Micro & RM Nimbus versions. It's very easy 🙂

For this experiment, I've used both my Acorn BBC Master 128 fitted with new LITHIUM LONG LIFE CMOS RTC BATTERY PACK, separate CUMANA dual 3.5" floppy drive case with built-in power supply containing Black Gotek USB Floppy drive emulator (as Drive A), Cable & SanDisk 16GB USB Stick & 3.5" TEAC FD-235F floppy drive (as Drive B) and my upgraded Slimline PC-186 with maximum 1536K RAM, SCSI2SD as HDD replacement & Gotek Floppy Emulator installed, loading from HDD using exactly the same settings including configured apps with a total of 21 fully customised easy access menu options via Function keys (as shown below) - the easy way, mentioned in BetaArchive Forum for more details, stored as SPC186 - Current SCSI2SD Back up.rar file - just in case my HDD gets accidentally blank formatted by mistake or faulty.

 

It wasn't easy creating 10 different menu options (both *.MCD & *.EXE files are stored in C:\MENU folder on HDD) especially it's both a pain and time consuming with entering / editing every Name, Pathname, Command Tail & Change of directory for each Function key, so I had to planned everything out in detail from scratch with all the time and effort has putting into it first by using both Microsoft Excel & Microsoft Word software (both of these documents are stored as RM NIMBUS MENU SCREEN.rar) as rough draft before creating and customising the final version on all 10 menu options (*.MCD files) using CONMENU.EXE file, so that I can make some last minute changes at any time on both documents without going through a huge hassle by changing the whole menus each time for the sake of changing only 1 menu option in any particular Function key.  

RM Nimbus PC-186 Customised Menu Options
Main Menu - WELCOME.MCD	Welcome Main Menu - F2 key	RM Nimbus Software Menu - NIMBUS.MCD
Databases Menu - F2 key	Word processing/text editing Menu - F4 key	Computer Languages Menu - F6 key
Other applications Menu - F8 key	RM Nimbus PC-186 Games Menu - PC186G.MCD	More GAMES Menu - F10 key
Other Games Menu - OGAMES.MCD	More GAMES Menu - F10 key	MicroSMILE Menu - F6 key
Others Menu - OTHERS.MCD	More APPLICATIONS Menu - MOREAPPS.MCD	More applications Menu - F10 key
More applications Menu - F10 key	Communications Menu - COMMS.MCD	IBM MODE Support Software Menu - IBM.MCD
More IBM MODE Support Software - F10 key	Configuration Options - CONFIG.MCD	Microsoft Windows - WIN.MCD