ZETRON 640 DAPT XTRA, Installation And Repair Manual, Page: 56 / 210

Communications Setup
44 025-9416
Control Characters
Some unusual and special control characters are often written to the screen during the initial
ZLINK interface. These symbols are normal and indicate that the terminal is attempting to hand-
shake with the Model 640 to establish a communications link. However, if the screen displays
strange characters and a ZLINK connection cannot be established, the “ansi.sys” driver may not
be properly installed on the office computer. The characters may include, but are not limited to
arrows, brackets, numbers, and other rather strange characters. To remedy the situation, add the
following line to the “config.sys” file on the computer’s boot disk:
DEVICE=ANSI.SYS
Jumper Settings
The Model 640 does not immediately recognize switch or jumper setting changes. After any
changes are made, turn the equipment off, then back on to reinitialize the hardware.
Active ZLINK Connections
The office computer (PC) can talk to the paging terminal through the phone lines by way of
modem, or through a local serial connection. Only one access method should be active at any
given time. Zetron recommends consistently using only one interface method to avoid accidental
communications conflicts.
CAUTION
Always turn off the computer or paging terminal before inserting or removing boards!
Zetron Communications Software
The ZLINK software is more sensitive to hardware configuration than dumb terminal emulator
programs such as Crosstalk. ZLINK may not work correctly, even when another communications
program runs okay on the same machine without changing anything. The steps below should
resolve any problems. Please note that once configured properly for ZLINK, other communica-
tion programs should still run without any problem.
Note: When ZLINK starts up, both the serial port and modem are reset to communicate
properly with the Model 640. There is no need to manually configure stop bits, parity,
etc. - ZLINK does it automatically.
Serial Ports
If the office computer is locally connected to the paging terminal and a link cannot be estab-
lished, this subsection provides some possible solutions.
A serial port is required for external modem and local connections to the paging terminal. If the
office computer does not already have a built-in serial port available, one may need to be
purchased and installed. Contact a computer repair and sales company for details and options.
ZLINK supports two serial ports directly (more can be addressed):