Siemens M20 Terminal Technical Description page 193

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5 (This Pin must not exceed Voltages >2V
during power on procedure to avoid a
change to bootmode!)
6
Note:
(1) Ignition signal > 5V for longer than 1 s has to be set to voltage > 2.8 V, remember that this signal has to be low when
switching off the M20 with AT command AT^SMSO, see Chapter
.
on page 111
(2) SW-DOWNLOAD: To switch the M20T to bootmode use the following procedure:
Apply > 8V to Pin 5 before or together with the supply voltage. The M20T switches to bootmode. Proceed according to
capt.8.5 (e.a.?) loading the SW using the RS 232-interface (9-pole SUB-D plug).
(3) POWER_OFF EXCEPTION HANDLING: In case of software hang-ups etc. the M20T can be switched off using the
following procedure (exception handling): Pin 3 must be applied with a voltage > 8V AND Pin 4 must be low (0V). To
switch on again, set ignition >5V (and Pin 2 <2V).
Fig. 8-2 Front view of Western plug 6-6 (male)
Follow instruction in chapter
8.5.4 M20T: HW Setup Terminal B4
1) Connect the M20Terminal to the PC with the serial cable.
2) Connect power supply of M20T to M20T; BUT do NOT connect power supply to mains!!!
3) Unscrew and remove top cover of M20T (Screwdriver Torx7).
Version 8 dated 15.03.00
AC: Line-out 600 Ohm
DC: Signal for initialisation of SW download for U(to Pin6)>8V
GND
8.5.5 "M20T: Booting for SW loading" on page 194
5.7 "Siemens-defined AT commands for enhanced functions"
.
Application notes
A
193