AN1500A South African Micro-Electronic Systems, AN1500A Datasheet - Page 6

• Manufacturer Part Number: AN1500A
• Description: Single Chip Telephone Demo Board
• Manufacturer: South African Micro-Electronic Systems

7.1 Setting a/b line connection
J1 allows selection of a/b line terminals to
easily adapt the demo board to various
PTT line connections:
7.2 Connecting a handset
A handset connected at Z2 should have the following
connections:
remark: observe polarity of the electret microphone
7.3 Setting dialing mode
By J2, a selection of 3 different dialing modes can be
made, 2 pulse (=LD) dialing modes and a DTMF
dialing mode.
If LD Mode is selected then it is possible to switch
into MF mode by pressing the ! key but the mode
will return to LD after a hookswitch operation or after
a Recall (flash). In LD mode pulsing is at 10 pulses
per second.
7.4 Setting line loss compensation (AGC)
Line loss compensation = line current dependent
gain setting of Tx and Rx amplifiers can be set by
jumper setting to 3 different modes : high, low and
no LLC (=default).
7.5 AC impedance
The Characteristic or output impedance of the SA2532K is set internally to 600 . No further components are
required. For a complex impedance refer to pt 11.
6/27
AN1500A
sames
sames
sames
sames
inner two pins (default)
J1
LD Mode
make/break
ratio 1:2
LLC 45 to 75mA
J2
J3
Handset
LD Mode
make/break
ratio 2:3
LLC 20 to 50mA
J2
outer two pins (optional)
J1
J3
J2
MF Mode
no LLC
J3