IMSTerm Remote Serial / Modem Support Pages

Setting up Serial devices over extended distances: The RS232 standard for cable is 30 metres. Line drivers typically offer up to 1250 metres at 19200 baud (mains powered) or 9600 baud (voltage taken from serial interface). The units used in our test configuration were Misco 1011 units; an equivalent unit is available from many sources. The key distinguishing feature is a 25 way D connector one end, with a 5-way screw terminal block to connect the long distance cable to.
Configuration: Server end: Moulded 9 to 25 way converters were used to attach the driver to the 9 way D port offered. This was to ensure a voltage was available to power the line driver. Because a link was already in place which was proving to be too long for the serial port to drive, a converter was soldered together (in this case a 9 way D male with 4 conductors soldered in place, on pins 2,3,5 & 6.) The four connections on the converter were inserted into the Rx+, Rx-, Tx+ and Tx- connections on the line driver. In this case the connections were: 2>Rx+ 3>Rx- 5>Tx+ 6>Tx-. The line driver can now be inserted in the cable run without modification to the existing cable. (The fifth connection, "protective ground", is offered, but only needed in high electrical noise environments, according to Misco tech support). Terminal end: The same configuration procedure was adopted, but this time using pins 2,3,4 & 5 on the 9 way connector, to link to the existing cable. This time, however, the four conductors that enter the screw terminal block need to be connected thus: The connector from Rx+ at the server is connected to Tx+ at the terminal. Rx- Tx- Tx+ Rx+ Tx- Rx- In our case, 2>Tx- 3>Tx+ 4>Rx- 5>Rx+ were the correct choices. The internal switches inside the driver cases were left as default, ie on,off,on,off at both ends, since both serial devices were DTE devices.
Lost characters when printing This is a recurrent report - usually happening after a few pages of printout. The classic symptom is that a character or characters will disappear from a line of text, but each subsequent line is fine until the same thing happens again a few lines further on. The problem is usually that the characters are being lost by unbufferd uarts - the chips that control serial port I/O. If your baud rate is greater than 9600, please ensure you have buffered uarts (types 16450 and 16550) in use. If you are in doubt, IMSD.EXE will advise you which type of uart is in use.
Old copies of IMSterm.exe One or two old copies of IMSTERM.EXE have surfaced recently, and caused some grief. A very few early REAL/32 copies had a difficulty which led to either Capslock freezing the emulator or printing being corrupted via the terminal. Although this was corrected almost immediately, some of the old copies are still on user sites. The cure is to run "Xdir IMSTERM.EXE /c /s" from the root directory of a hard drive, to determine the checksum of all copies of IMSTERM.EXE on that system. The earliest correct version carries checksum 64FC dated 13/10/95 (timestamp 7.54) - any version older than that should be replaced.
You may download this version here.
IMSterm under REAL/32. Running IMSterm on a REAL/32 server has good implications for remote maintenance, especially when Remote Windows is launched with REAL/32 7.6, since that will include file transfer in either direction. Since both the server and IMSterm use the same task switching keys by default, you are advised to opt for a different set of switching keys for IMSterm. Provided you don't plan to use anything other than text screens, a Wyse terminal will be sufficient to run the IMSterm session to the remote server! The two difficulties might be screen colours (where colour differentiation on a mono terminal screen might be a problem), and some garbage may be placed on the terminal
Quick cable set up for Wyse and C192 Terminals, and PCs running IMSTerm under Real/32: 1) The cable connections:-
25 way host to 25 way terminal: 3-2 2-3 6-20 7-7
25 way host to 9 way terminal: 3-3 2-2 6-4 7-5
9 way host to 25 way terminal: 2-2 3-3 6-20 5-7
9 way host to 9 way terminal: 2-3 3-2 6- 4 5-5
Please refer to your Installation manual appendix B for full cabling instructions.
2) Set the Host flow control to "Transmit DSR = YES". All other options on this screen to "No".
3) Set the terminal to "DTR" flow control, to match the DSR. In the case of IMSTerm, select Hard flow control.
Finally: Check the baud rates match at both ends, that Parity is set to EVEN, Databits are set to 8 and stop bits set to 1. If you have unbuffered UARTS on your server or PC terminal, be aware of the danger of lost characters at high baud rates. Your installation should now run smoothly.
Quick set up for IMSTerm Remote with Courier Sportster 14400 modems Preparation
Check your IMSTerm.exe is release 5.01, Checksum 64FC. or later.
At the TERMINAL end: Set the IMSTerm flow control to Hardware. The modem should have switches 3,5,8 set down. Use the following string at the IMSTerm (PC) end:
AT ATtention
&F load factory settings
E0 Local Echo Off
&B1 Fix baud rate from Modem to Com port
&R2 Set Hardware (RTS) flow control
&W Write the configuration to NVRAM
And the hang up string:
SERVER/HOST setup: Set the flow control to RTS/CTS protocols. On the server/host modem, set modem switches 3,5,8 down. Use the following string in the setup program at the server end:
AT ATention
E0 Local Echo Off
&B1 Fix the baud rate from Modem to Com port
&H1 Set hardware (CTS) flow control
&R2 Set Hardware (RTS) flow control
Q2 Suppress result codes in answer mode
S0=1 Answer incoming calls on first ring
&W Write the configuration to NVRAM
And the hang up string:
Copyright 1997-2002 Intelligent Micro Software. All rights reserved. Information in this document is subject to change without notice. Other products and companies referred to herein are trademarks or registered trademarks of their respective companies or mark holders.
Last modified: Wednesday November 27, 2002.