Specifications

HAPTER 4 – DEVELOPER BOARD AND SCHEMATICS
29
Multi-Tech Systems, Inc. Universal Socket Developer Guide
Board Components
Schematic
Jumper Label
PCB Label or
Location
Description
J19
Next to
stereo jack.
Allows a stereo jack feed. Default is ON. If ON, then left and right stereo channels
are combined and form a mono channel.
J25& J26
GND LUG
Ground lug.
JP1
Speaker
Mutes the speaker. Default positions are 1 and 2 (speaker is not muted).
JP13
USB PWR
Set either 5V or 3.3V for USB_VBUS line (supplied by the VCC of the USB jack).
JP16
JTAG
JTAG header.
JP17
Mosquito
Mosquito header. If used to debug the SocketModem while using the USB port,
remove the JP13 to disconnect USB_VBUS.
JP18
MOD PWR
Power feed (Vcc) SocketModem module. (X3).
JP19& JP20
Debugging probes pins for SocketModem.
JP21 & JP22
Antenna
Antenna ground select.
JP24 & JP25
Antenna
Antenna ground select.
JP28
Handset
Digital
Digital handset jack, 4 pin connector (not labeled on schematic).
JP49
SPK
Speaker jack header.
JP50
MIC
Microphone jack header.
JP83 & JP84
ATtiny25
ATtiny25 6-pin programmer headers.
JP85
1.8V 5V
Selects operating voltage (1.8v or 5v) for the ATtiny25v micro-controller.
JP87
Board PWR
Select
The 5V/3.3V regulator. Factory default operating voltage is 5V.
Warning:
 Verify that the 5V/3.3V jumper matches your SocketModem’s
requirements. If this jumper is set incorrectly, you could damage the
SocketModem and/or Test/Demo board.
 Use only the Multi-Tech Systems supplied transformer with the
Test/Demo board. Using any other power source voids the warranty and
will likely damage the Test/Demo board and SocketModem.
JP88
JTAG PWR
Select
Selects operating voltage (5v or 3.3v) for the JTAG.
JP89
SER TL
Testing interface (debugging) for the serial TTL signals.
JP90
RS232
Testing interface (debugging) for the RS-232 signals.
S1
Next to 9VDC
Power Jack
Board input power switch (not labeled on schematic).
S5
RESET
Reset push switch.
Jxx indicates jacks.