DIALOG

DIALOG is the original communications program supplied with the Monolog system. Written in Borland Turbo Assembler, it provides a terminal interface to the Monolog unit and handles the download of call records to disk. Two versions were supplied with the original documentation (dated 24 January 1990) — DIALOG1.COM for COM1 and DIALOG2.COM for COM2 — both at version 1.7a. A later version 1.8 is known to have been released, but documentation for it has not been found.

Session Example

The following shows a typical DIALOG session — startup, modem dial-out and sign-on to a Monolog unit:

The sign-on response identifies the unit by serial number (10521), firmware version (0.82) and RAM configuration (32K). The time on and last on timestamps record the current session start and the previous sign-on respectively. calls logged gives the number of records currently held in RAM.

Connection Modes

DIALOG supports two connection methods, both over the same 25-way D-type connector on the Monolog unit:

Command Line Automation

The full dial-up sequence could be automated by invoking DIALOG with command line parameters, eliminating the need for interactive entry at startup:

When invoked this way, DIALOG automatically dials the number, signs on with the supplied password, waits at the prompt and then exits — leaving the operator to issue commands manually, or for a script to take over. Only data received in response to a DL or AL command is written to the download file; all other terminal output is displayed on screen only.

Download Protocol

The most significant discovery in reverse-engineering DIALOG was that Monolog switches serial modes mid-session when a download is initiated. The terminal session runs at 300 baud 7E1; but when DL or AL is issued, the unit silently switches to 300 baud 8N1 for the binary block transfer, then returns to 7E1 on completion. DIALOG handles this automatically.

Block Transfer Sequence

The download uses a simple NAK/ACK handshake protocol:

Once received, the binary packed block data is decoded by DIALOG into the readable call record format before writing to disk. The binary packing compresses each record — storing date, time, duration, digits and call type in a compact representation — which DIALOG expands into the familiar column-aligned text format used by CHECKLOG and PRINTOUT.

Limitations & Legacy

DIALOG was written for MS-DOS and relies on direct hardware port access for serial communication. As a 16-bit real-mode application it cannot run natively on any 64-bit operating system. It can be run under DOSBox or similar emulators, but the original software is no longer a practical tool for day-to-day use.

The protocol and record format have however been fully reverse-engineered, making it possible to replicate DIALOG's behaviour accurately in modern programming languages. The Python reimplementation — dialog.py — targets the Mark II's direct RS-232 port at 9600 baud and is available in the Downloads section.