There are quite a few programs available now that use a zero crossing data slicer, or a sound card interface to enable a Personal Computer to decode digital signals off the airwaves. Although the audio out signal can be used to feed the data slicer or sound card, the filtering in the AF section can limit the bandwidth or distort the signal.
It is possible to tap into the basband audio of a scanner to get a raw unfiltered signal which is optimal for driving a data slicer or sound card. This is done by taping into the discriminator chip and catching the AF before it enters the AF filtering and amplification section of the receiver.
Below is a list of scanners and the discriminator chip used in the scanner. Also shown for each entry is a circuit symbol and the RF-Input, scan control, and baseband audio pins for each discriminator.
CKT RF-in SCAN AUDIO
SCANNER NFM CHIP TYPE SYMBOL Pin Pin BASEBAND
MPS5071 n/a 16 13 9
AR-1000 TA-7787AF IC-4 ? ? ?
AR-2002 MC-3357P IC-4 16 13 9
AR-3000 MC-3357P ? 16 13 9
AR-800 MC-3361N IC-200 16 13 9
AR-900 MC-3361N IC-201 16 13 9
AR-950 MC-3361N IC-201 16 13 9
BC-100XL MC-3359P IC-1 18 15 10
BC-100XLT TK-10421M-2 IC-401 20 16 11
BC-200XLT TK-10421M-2 IC-401 20 16 11
BC-205XLT TK-10421M-2 IC-401 20 16 11
BC-250 ? IC-3 16 13 9
BC-2500XLT TK-10930VTL IC-201 24 - 12-FM 13-AM
BC-350A NJM-3359D-A IC-3 18 15 10
BC-400XLT NJM-3359D-A IC-1 18 15 10
BC-560XLT NJM-3359D-A IC-1 18 15 10
BC-700A NJM-3359D-A IC-3 18 15 10
BC-760XLT NJM-3359D-A IC-2 18 15 10
BC-800XLT MC-3359P IC-1 18 15 10
BC-8500XLT MC-3361BP IC-9 16 13 9
BC-855XLT TK-10421M-2 IC-401 20 16 11
BC-890XLT NJM-3359D-A IC-3 18 15 10
BC-950XLT NJM-3359D-A IC-2 18 15 10
HX-1000 TK-10420 U-201 16 13 9
MR-8100 NJM-3359D-A IC-3 18 15 10
MX-5000 MC-3357P IC-4 16 13 9
MX-7000 MC-3357P IC-4 16 13 9
PRO-2002 MC-3357P IC-101 16 13 9
PRO-2003 MC-3357P IC-104 16 13 9
PRO-2004 NFM/AM TK-10420 IC-2 16 13 9
PRO-2004 WFM KB4419A IC-1 1 ? 6
PRO-2005 NFM/AM TK-10420 IC-2 16 13 9
PRO-2005 WFM KB4419A IC-1 1 ? 6
PRO-2006 NFM/AM TK-10420 IC-2 16 13 9
PRO-2006 WFM KB4419A IC-1 1 ? 6
PRO-2011 TK-10420 IC-1 16 13 9
PRO-2020 MC-3357P IC-101 16 13 9
PRO-2021 TK-10420 IC-2 16 13 9
PRO-2022 MC-3361N IC-1 16 13 9
PRO-2024 MC-3361N IC-2 16 13 9
PRO-2025 NJM-3359D-A IC-1 18 15 10
PRO-2026 NJM-3359D-A IC-7 18 15 10
PRO-2027 MC-3361N IC-2 16 13 9
PRO-2028 NJM-3359D-A IC-2 18 15 10
PRO-2030 NJM-3359D-A IC-3 18 15 10
PRO-2035 TK-10420 IC-2 16 13 9
PRO-2042 TK-10420 IC-2 16 13 9
PRO-23 MC-3361BD IC-1 16 13 9
PRO-26 NFM/AM TK-10930V IC-14 24 - 12-NFM 13-AM
PRO-26 WFM TK-10489M IC-16 20 16-17 11
PRO-31 TK-10420 IC-1 16 13 9
PRO-32 TK-10420 IC-101 16 13 9
PRO-34 TK-10420 IC-101 16 13 9
PRO-35 TK-10421M-2 IC-401 20 16 11
PRO-36 TK-10420 IC-101 16 13 9
PRO-37 TK-10420 IC-101 16 13 9
PRO-39 MC-3361N IC-201 16 13 9
PRO-41 MC-3359P IC-1 18 15 10
PRO-42 MC-3361N IC-2 16 13 9
PRO-43 TK-10427/-10420 IC-301 16 13 9
PRO-44 MC-3361N IC-201 16 13 9
PRO-46 TK-10421M-3LT IC-401 20 16 11
PRO-51 MC-3361BD IC-1 16 13 9
PRO-60 ? IC-301 16 13 9
R-1600 NJM-3359D-A IC-2 18 15 10
R-4030 TK-10421M-2 IC-401 20 16 11
SR-15 TK-10421D-2 IC-1 16 13 9
TurboScan 2 3130-6056-502 U-201 18 ? 10 or 16