ComputerCraft Wiki - User contributions [en]

Modem (API)

2013-08-07T05:51:29Z

Iownall555: Removed notice

:''This page is for the modem API. For the blocks, see [[Modem]].''

As of ComputerCraft 1.5, channels have been added - channels are essentially networks which can be opened, closed and listened on by any computer within range, without need of independant computer IDs. To interact with channels, one must wrap or interact directly with the peripheral as opposed to the previous interaction with the Rednet API.

<table style="width: 100%; border: solid 1px black; margin: 2px; border-spacing: 0px;">
<tr><td colspan="2" style="font-weight: bold; font-size: large; padding-bottom: .3em; border-bottom: solid #C9C9C9 1px; background: #D3FFC2; line-height:28px;">
[[File:Grid_disk.png|24px]]  
Modem (API)
</td></tr>

<tr><td style="width: 350px; background: #E0E0E0; padding: .4em; font-weight:bold;">Method Name</td><td style="background: #E0E0E0; padding: .4em; font-weight:bold;">Description</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.isOpen]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Checks to see if ''channel'' is open</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.open]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Opens ''channel'' to allow for listening. The channel specified must be larger than 0 and less than 65535</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.close]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Closes an open channel to disallow listening</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.closeAll]]()</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Closes all open channels</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.transmit]]({{type|int}} channel, {{type|int}} replyChannel, {{type|string}} message)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Transmits a message on the specified channel</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.isWireless]]()</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Returns true if the modem is wireless; false if it is wired</td></tr>
</table>
{| class="wikitable" width="100%"
! colspan="1" | Event Name
! colspan="1" | Description
! colspan="1" | Parameters
|-
! scope="row" | modem_message
|Fired when a modem message is received.
|{{type|string}} modemSide, {{type|int}} senderChannel, {{type|int}} replyChannel, {{type|string}} message, {{type|number}} distance
|}

==Sending Messages==
Sending messages is simple and does not require that you open any channels. Simply use the transmit function like so:
local modem = peripheral.wrap("right") --Wraps the modem on the right side.
modem.transmit(3, 1, "Hello world!")
peripheral.call("right", "transmit", 3, 1, "This will also work!")

What did that do? First I wrapped the peripheral in order to interact with it. Second, I used modem.transmit(channel, replyChannel, message) in order to send my message. In case you were wondering, the reply channel is captured by the listening computer and suggests which channel they should reply on.

==Receiving Messages==
Receiving messages requires that you be familiar with events. As of this moment, there is no API which cuts out events from the process. Here is an example of how to receive messages:
local modem = peripheral.wrap("left")
modem.open(3)--Open channel 3 so that we can listen on it
local event, modemSide, senderChannel,
replyChannel, message, senderDistance = os.pullEvent("modem_message")
print("I just received a message from: "..senderChannel)
print("I should apparently reply on: "..replyChannel)
print("The modem receiving this is located on the "..modemSide.." side")
print("The message was: "..message)
print("The sender is: "..senderDistance.." blocks away from me.")

So what did I do? Quite simply, I called os.pullEvent() with the string argument "modem_message", which blocks all other events from being returned. When the "modem_message" event is captured, it returns the arguments: event, modemSide, senderChannel, replyChannel, message, senderDistance. I captured these and then printed them out.

== Modem Limitations ==
* You can only open 128 channels at any given time.
* The maximum channel you can open is 65535.
* You can listen on more than one channel at a time. For example, if the modem has channel 3 and channel 5 open, and somebody sends a message on channel 5, the modem will receive it. If a message is sent on channel 3, the modem will also receive the message.
* Sending messages does not require you to open any channels prior to sending it.
* If you aren't receiving a message when you think you should, check to make sure that you have opened the channel first.
* Modems and channels are not secure - if you are sending a message using the Modem API, messages are still available to any computer listening on the sent channel.

[[Category:Peripheral APIs]]

Modem.isOpen

2013-08-07T05:46:39Z

Iownall555: Adjusted the args data type

{{Function
|name=modem.isOpen
|args={{type|int}} channel
|api=Modem
|addon=ComputerCraft
|desc=Checks whether or not a certain channel is open.
|examples=
{{Example
|desc=Checks whether the computer is listening on this channel.
|code=modem.isOpen(1)
}}
}}

Modem.isWireless

2013-08-07T05:41:40Z

Iownall555: Created page with "{{Function |name=modem.isWireless |returns={{type|boolean}} isWireless |api=Modem |addon=ComputerCraft |desc=Returns true if a modem is wireless, false if it's wired. |example..."

{{Function
|name=modem.isWireless
|returns={{type|boolean}} isWireless
|api=Modem
|addon=ComputerCraft
|desc=Returns true if a modem is wireless, false if it's wired.
|examples=
{{Example
|desc=Returns true if a modem is wireless, false if it's wired.
|code=modem.isWireless()
}}
}}

Modem.transmit

2013-08-07T05:37:57Z

Iownall555: Created page with "{{Function |name=modem.transmit |args={{type|int}} channel, {{type|int}} replyChannel, {{type|string}} message |api=Modem |addon=ComputerCraft |desc=Sends a message and a repl..."

{{Function
|name=modem.transmit
|args={{type|int}} channel, {{type|int}} replyChannel, {{type|string}} message
|api=Modem
|addon=ComputerCraft
|desc=Sends a message and a reply channel over the specified channel.
|examples=
{{Example
|desc=Sends a message and a reply channel over the specified channel.
|code=modem.transmit(1, 2, "Hello world!")
}}
}}

Modem.closeAll

2013-08-07T05:34:41Z

Iownall555: Created page with "{{Function |name=modem.closeAll |api=Modem |addon=ComputerCraft |desc=Closes all channels on the modem. |examples= {{Example |desc=Closes all channels on the modem. |code=mod..."

{{Function
|name=modem.closeAll
|api=Modem
|addon=ComputerCraft
|desc=Closes all channels on the modem.
|examples=
{{Example
|desc=Closes all channels on the modem.
|code=modem.closeAll()
}}
}}

Modem.close

2013-08-07T05:30:56Z

Iownall555: Created page with "{{Function |name=modem.close |args={{type|int}} channel |api=Modem |addon=ComputerCraft |desc=Closes the specified channel. |examples= {{Example |desc=Closes the specified ch..."

{{Function
|name=modem.close
|args={{type|int}} channel
|api=Modem
|addon=ComputerCraft
|desc=Closes the specified channel.
|examples=
{{Example
|desc=Closes the specified channel.
|code=modem.close(1)
}}
}}

Modem.open

2013-08-07T05:26:32Z

Iownall555: Created page with "{{Function |name=modem.open |args={{type|int}} channel |api=Modem |addon=ComputerCraft |desc=Opens the specified channel to allow listening for messages. |examples= {{Example..."

{{Function
|name=modem.open
|args={{type|int}} channel
|api=Modem
|addon=ComputerCraft
|desc=Opens the specified channel to allow listening for messages.
|examples=
{{Example
|desc=Opens the specified channel to allow listening for messages.
|code=modem.open(1)
}}
}}

Modem (API)

2013-08-07T05:17:03Z

Iownall555: Adjusted the event to reflect the current parameters and did minor adjustments to method table.

{{NeedsWork|Need to add pages for missing functions --[[User:Cranium|Cranium]] 17:13, 10 May 2013 (MSK)}}

:''This page is for the modem API. For the blocks, see [[Modem]].''

As of ComputerCraft 1.5, channels have been added - channels are essentially networks which can be opened, closed and listened on by any computer within range, without need of independant computer IDs. To interact with channels, one must wrap or interact directly with the peripheral as opposed to the previous interaction with the Rednet API.

<table style="width: 100%; border: solid 1px black; margin: 2px; border-spacing: 0px;">
<tr><td colspan="2" style="font-weight: bold; font-size: large; padding-bottom: .3em; border-bottom: solid #C9C9C9 1px; background: #D3FFC2; line-height:28px;">
[[File:Grid_disk.png|24px]]  
Modem (API)
</td></tr>

<tr><td style="width: 350px; background: #E0E0E0; padding: .4em; font-weight:bold;">Method Name</td><td style="background: #E0E0E0; padding: .4em; font-weight:bold;">Description</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.isOpen]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Checks to see if ''channel'' is open</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.open]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Opens ''channel'' to allow for listening. The channel specified must be larger than 0 and less than 65535</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.close]]({{type|int}} channel)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Closes an open channel to disallow listening</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.closeAll]]()</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Closes all open channels</td></tr>

<tr style="background-color: #FFFFFF;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.transmit]]({{type|int}} channel, {{type|int}} replyChannel, {{type|string}} message)</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Transmits a message on the specified channel</td></tr>

<tr style="background-color: #E8E8E8;"><td style="border-top: solid #C9C9C9 1px; padding: .4em;">[[modem.isWireless]]()</td>
<td style="border-top: solid #C9C9C9 1px; padding: .4em;">Returns true if the modem is wireless; false if it is wired</td></tr>
</table>
{| class="wikitable" width="100%"
! colspan="1" | Event Name
! colspan="1" | Description
! colspan="1" | Parameters
|-
! scope="row" | modem_message
|Fired when a modem message is received.
|{{type|string}} modemSide, {{type|int}} senderChannel, {{type|int}} replyChannel, {{type|string}} message, {{type|number}} distance
|}

==Sending Messages==
Sending messages is simple and does not require that you open any channels. Simply use the transmit function like so:
local modem = peripheral.wrap("right") --Wraps the modem on the right side.
modem.transmit(3, 1, "Hello world!")
peripheral.call("right", "transmit", 3, 1, "This will also work!")

What did that do? First I wrapped the peripheral in order to interact with it. Second, I used modem.transmit(channel, replyChannel, message) in order to send my message. In case you were wondering, the reply channel is captured by the listening computer and suggests which channel they should reply on.

==Receiving Messages==
Receiving messages requires that you be familiar with events. As of this moment, there is no API which cuts out events from the process. Here is an example of how to receive messages:
local modem = peripheral.wrap("left")
modem.open(3)--Open channel 3 so that we can listen on it
local event, modemSide, senderChannel,
replyChannel, message, senderDistance = os.pullEvent("modem_message")
print("I just received a message from: "..senderChannel)
print("I should apparently reply on: "..replyChannel)
print("The modem receiving this is located on the "..modemSide.." side")
print("The message was: "..message)
print("The sender is: "..senderDistance.." blocks away from me.")

So what did I do? Quite simply, I called os.pullEvent() with the string argument "modem_message", which blocks all other events from being returned. When the "modem_message" event is captured, it returns the arguments: event, modemSide, senderChannel, replyChannel, message, senderDistance. I captured these and then printed them out.

== Modem Limitations ==
* You can only open 128 channels at any given time.
* The maximum channel you can open is 65535.
* You can listen on more than one channel at a time. For example, if the modem has channel 3 and channel 5 open, and somebody sends a message on channel 5, the modem will receive it. If a message is sent on channel 3, the modem will also receive the message.
* Sending messages does not require you to open any channels prior to sending it.
* If you aren't receiving a message when you think you should, check to make sure that you have opened the channel first.
* Modems and channels are not secure - if you are sending a message using the Modem API, messages are still available to any computer listening on the sent channel.

[[Category:Peripheral APIs]]