Texas Instruments TI-92+, Tip List

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programs using the SEND button in the GraphLink windows. This can usually be fixed by executing
Recieve or Get Screen from the GraphLink menu.
If you use the GraphLink software to develop CBL or CBR programs, you may want to build the
switch-box circuit (described in tip [5.7] below) into your BCC.
(Credit to Frank Mori Hess for the cable designs and documentation)
[5.7] GraphLink switchbox aids CBR/CBL programming
If you use the GraphLink software to write TIBasic programs for the CBR or CBL, you do a lot of cable
swapping during program development. You must connect the calculator to the GraphLink cable to
download the software, then connect the calculator to the CBL to test your software. This cable
swapping wears out the cable and connectors, and can be avoided with a simple switchbox:
J1, J2 and J3 are female 2.5mm stereo jacks, and SW1 is a triple-pole, double-throw (3PDT) toggle
switch. SW1 simply switches the three GraphLink cable conductors between J1 and J2, so the
calculator connects to J3, the PC connects to J1, and the CBL connects to J2. Even though you must
remember to put the switch in the proper position, the switchbox still eliminates the cable swapping.
Because of the low currents involved, SW1 should be a 'dry circuit' switch, with gold contacts.
Unfortunately, 3PDT switches with gold contacts are not easy to get. The alternative is to use a switch
with silver-plated contacts. Eventually, the silver will oxidize and communications will fail, and the
switch will need to be replaced. However, I have been using such a switch for over a year with no
failure yet. A typical switch is the C&K 7301SYZQE, which can be obtained from Mouser Electronics
(www.mouser.com) as their part number 611-7301-001. Mouser also carries a high-quality 2.5mm
stereo jack, their part number 161-3307.
If you build your own GraphLink cable, as shown in tip [5.6], you can build this switchbox into the same
enclosure and save a 2.5mm jack.
[5.8] Opening variables in GraphLink changes some characters
Some characters in strings are changed by the GraphLink software if file variables using these
characters are opened. This is a problem if the program is distributed to users as a file created with
GraphLink. The characters will not be converted if the program is simply sent from GraphLink with Link
Send, and the program will work correctly. However, if the user first opens the program file, then the
characters are converted and the program will not work. This tip applies to AMS 2.05 and the PC
version 2.1 of the GraphLink software.
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