TB7100 Service Manual General Information 91
© Tait Electronics Limited October 2005
6.8 Computer-Controlled Test Mode (CCTM)
The servicing procedures require the transmitter or receiver modules to be 
placed in the computer-controlled test mode. In this mode CCTM 
commands can be entered at the test PC. These commands are then relayed 
via the test unit to the module. Certain CCTM commands cause the 
module to carry out particular functions; others read particular settings and 
parameter values in the module. The CCTM commands of use in servicing 
the modules are listed in Table 6.3 to Table 6.6, grouped according to 
category.
Terminal Program
for CCTM
Use the HyperTerminal utility which is supplied with Microsoft Windows. 
As a preliminary, first select the settings for the communications port as 
follows:
1. Open the terminal program. (In the case of HyperTerminal, click 
Start > Programs > Accessories > Communications > HyperTerminal.)
2. In the terminal program first select the COM port to which the 
module is connected. Then select the following settings for the port:
■ bits per second : 19200
■ data bits : 8
■ parity : none
■ stop bits : 1
■ flow control : none
3. Click the OK button (or equivalent).
4. Save the file with the port settings under a suitable name. 
For subsequent sessions requiring the terminal program, open this 
file.
Invoking CCTM Using the terminal program, place the module in CCTM as follows:
1. Enter the character ^ to reset the module.
2. As soon as the module is reset, the letter v is displayed. (If an 
uppercase letter V appears, this implies a fault.)
3. Immediately the letter v is displayed, enter the character%. 
(The character% must be entered within half a second of the letter v 
appearing.)
4. If the character% is accepted, the character – is displayed in response, 
and the message CL appears on the base station display. This implies 
that the module has entered CCTM. If the attempt fails, repeat Step 1 
to Step 3.