The 25 way
Pin number, name and mnemonic:
2 | Transmit Data | TxD |
3 | Receive Data | RxD |
4 | Request to Send | RTS |
5 | Clear to Send | CTS |
6 | Data Set Ready | DSR |
7 | Signal Ground/Supply Ground | SG |
8 | Data Carrier Detect | DCD |
9 | Power In | PI |
15 | Power In | PI |
20 | Data Terminal Ready | DTR |
22 | Ring Indicator | RI |
Supplying power to the modem
The Delta Plus MOBILE II GSM/GPRS modem is powered via the RS232 interface connector. Pins 9 and/or 15 require a +7 to +24 Volts DC supply (issue F. board) Earlier issues of the board require +7 to +15Volts. The modem consumes 0.3 Watts. (See appendix). The supply to the modem is floated across internal SuperCaps. These devices hold a considerable charge and will allow the modem LED’s to continue to function for several minutes after the removal of the power supply. This enables the modem to be used in environments where the power supply is either intermittent and/or inadequate (within reason) for a conventional modem product.
Battery powered version.
The GSM/GPRS modem is also available as a battery powered device. The battery employed in the modem is a Lithium Ion Polymer type and is subject to a minimum duty cycle of 1000 operations.
The battery is fitted in addition to the “Super Caps” that are present in the standard modem and will power the modem for approximately two minutes after the external supply has been removed. This is regardless of whether or not the modem is on line. When the modem shuts down it will issue a “Goodbye” message to the interface.
Additionally the modem can be switched off using an AT command. The AT+K command will shutdown the entire modem (not just the Sony Ericsson module as is the case with other ASLH 306 products) within 15 seconds. If the power supply to the modem is not removed within 30 seconds
ASL Holdings Limited | 19/09/2005 | 6 |
Draft Copy Version 2c |
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