Evaluation Kit for CMX612

EV6120

© 2000 Consumer Microcircuits Limited

21

UM6120/1

1.6.3.5

BT, ETSI and Bellcore type 2 demonstration

See flowchart in CMX612 datasheet (application notes section) for more information.

In ‘Feature Phone’ mode, the local speech path is enabled and muted when a CAS tone is detected

(when the CMX612 DET output is set in tone alert mode, termed early mute). Also signals from the

line, e.g. CAS tone, will be taken from the Rx side of the 2 to 4 wire interface.

In ‘Adjunct Box’ mode, the link to an external telephone, socket J2, is muted when a valid CAS tone

has been received (when CMX612 IRQN pin goes low in tone alert mode, termed late mute).

If the EV6120 is linked to a PC, see section 1.6.2, the point at which muting occurs can be toggled

between early and late.

Counters record the number of times muting has occurred (M) and the number of times a valid CAS

tone has been detected (C). The counts are displayed on row 3 of the LCD.

DTMF digit ‘D’ is transmitted on to the phone line as an acknowledgement tone. If the EV6120 is

linked to a PC other DTMF digits can be sent as an acknowledgement. CLI message parameters are

displayed on the top two rows of the LCD.

Whilst the acknowledgement is being transmitted testpoint TP19, labelled CAS, will be HI. This 60mS

pulse can be fed back to a CLI simulator for CAS performance testing.

1.6.3.6

(Stuttered) Dial Tone detect Algorithm Demonstration.

This is a simplified demonstration of the algorithm running in continuous mode only. The constants

are fixed to default values and only the resulting dial or stuttered dial tone detect figures are shown.

When the ‘SEL’ button is pressed the demonstration will halt at the end of the current test cycle.

During the idle period between tests the LED marked ‘MW’ will indicate the result of the last test. i.e. if

a stuttered dial tone was detected the LED will be on and if a normal dial tone was detected the LED

will be off.