Specifications

Chapter 1 – Universal Socket Connectivity
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342C) 11
Pin
Signal
Name
I/O
Type
Description
24 –RESET I
Device Reset (with pull-up).
The active low –RESET input resets the device logic and returns the configuration of
the device to the original factory default values of "stored values" in the NVRAM.
–RESET is tied to VCC through a time-constant circuit for “Power-on-Reset”
functionality. The module is ready to accept commands after a fixed amount of time
after power-on or reset.
Model Time Constant "X" Time Minimum Reset Pulse*
MT5600SMI 250 ms 6 seconds 100us
MT5656SMI 250 ms 6 seconds 100us
MT5634SMI 400 ms 6 seconds 100us
MT2456SMI-22 250 ms 6 seconds 100us
MT2456SMI-IP 250 ms 6 seconds 100us
MTXCSEM 250 ms 6 seconds 100us
MT128SMI 200 ms 6 seconds 100us
MTS2BTSMI 250 ms 6 seconds 100us
*The SocketModem device may respond to a shorter reset pulse.
Wireless GSM/GPRS and CDMA
Reset. This signal is used to force a reset procedure by providing low level during
reset of at least 500us. The signal is considered an emergency reset only. A reset
procedure is already driven by internal hardware during the power-up sequence.
This signal can also be used to provide a reset to an external device. It then acts as
an output. If no external reset is necessary, this input can be left open. If used
(emergency reset), it has to be driven by an open collector or an open drain.
26 GND GND
Logic Ground.
29 LED DCD O
DCD LED Indicator (Active High). Output from 74LCX14 with a 1000 Ohms resistor in
series.
SocketWireless Bluetooth (MTS2BTSMI): When lit, indicates a connection. No series
resistor.
30 LED RX O
RX LED Indicator (Active High). Output from 74LCX14 with a 1000 Ohms resistor in
series.
SocketWireless Bluetooth (MTS2BTSMI): No series resistor.
31 LED DTR O
DTR LED Indicator (Active High). Output from 74LCX14 with a 1000 Ohms resistor in
series.
SocketWireless Bluetooth (MTS2BTSMI): No series resistor.
32 LED TX O
TX LED Indicator (Active High). Output from 74LCX14 with a 1000 Ohms resistor in
series.
SocketWireless Bluetooth (MTS2BTSMI): No series resistor.
33 –RTS I
Request to Sent (Active Low). –RTS signal is used for hardware flow control. –RTS
input ON (low) indicates that the DTE is ready to send data to the modem. In the
command state, the modem ignores –RTS.
Note: When the –RTS pin is not in use, it should be tied low.
34 –RXD O
Received Data. The module uses the RXD line to send data to the DTE and to send
module responses to the DTE. In command mode, –RXD data presents the module
responses to the DTE. Module responses take priority over incoming data when the two
signals are in competition for –RXD. When no data is transmitted, the signal is held in
mark condition.
35 –TXD I
Transmitted Data. The DTE uses the –TXD line to send data to the module for
transmission or to transmit commands to the module. The DTE should hold this circuit
in the mark state when no data is being transmitted or during between intervals
between characters.
36 –RI or
PIO5
O
RING (Active Low). Incoming ring signal from phone.
Ring Indicate. –RI output ON (low) indicates the presence of an ON segment of a ring
signal on the telephone line. The modem will not go off-hook when –RI is active; the
modem waits for –RI to go inactive before going off-hook.
SocketWireless
Bluetooth (MTS2BTSMI): PIO5 – User definable I/O pin PIO5.
Strobes 1/sec for slave indication.
37 –DSR or
PIO7
O
Data Set Ready (Active Low). –DSR indicates module status to the DTE. –DSR OFF
(high) indicates that the DTE is to disregard all signals appearing on the interchange
circuits except Ring Indicator (–RI). It reflects the status of the local data set and does
not indicate an actual link with any remote data equipment.
SocketWireless
Bluetooth (MTS2BTSMI): PIO7 – User definable I/O pin PIO7.
Defaults as input.