Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/Documentation/isdn/INTERFACE b/Documentation/isdn/INTERFACE
new file mode 100644
index 0000000..5df17e5
--- /dev/null
+++ b/Documentation/isdn/INTERFACE
@@ -0,0 +1,759 @@
+$Id: INTERFACE,v 1.15.8.2 2001/03/13 16:17:07 kai Exp $
+
+Description of the Interface between Linklevel and Hardwarelevel
+ of isdn4linux:
+
+
+ The Communication between Linklevel (LL) and Hardwarelevel (HL)
+ is based on the struct isdn_if (defined in isdnif.h).
+
+ An HL-driver can register itself at LL by calling the function
+ register_isdn() with a pointer to that struct. Prior to that, it has
+ to preset some of the fields of isdn_if. The LL sets the rest of
+ the fields. All further communication is done via callbacks using
+ the function-pointers defined in isdn_if.
+
+ Changes/Version numbering:
+
+ During development of the ISDN subsystem, several changes have been
+ made to the interface. Before it went into kernel, the package
+ had a unique version number. The last version, distributed separately
+ was 0.7.4. When the subsystem went into kernel, every functional unit
+ got a separate version number. These numbers are shown at initialization,
+ separated by slashes:
+
+ c.c/t.t/n.n/p.p/a.a/v.v
+
+ where
+
+ c.c is the revision of the common code.
+ t.t is the revision of the tty related code.
+ n.n is the revision of the network related code.
+ p.p is the revision of the ppp related code.
+ a.a is the revision of the audio related code.
+ v.v is the revision of the V.110 related code.
+
+ Changes in this document are marked with '***CHANGEx' where x representing
+ the version number. If that number starts with 0, it refers to the old,
+ separately distributed package. If it starts with one of the letters
+ above, it refers to the revision of the corresponding module.
+ ***CHANGEIx refers to the revision number of the isdnif.h
+
+1. Description of the fields of isdn_if:
+
+ int channels;
+
+ This field has to be set by the HL-driver to the number of channels
+ supported prior to calling register_isdn(). Upon return of the call,
+ the LL puts an id there, which has to be used by the HL-driver when
+ invoking the other callbacks.
+
+ int maxbufsize;
+
+ ***CHANGE0.6: New since this version.
+
+ Also to be preset by the HL-driver. With this value the HL-driver
+ tells the LL the maximum size of a data-packet it will accept.
+
+ unsigned long features;
+
+ To be preset by the HL-driver. Using this field, the HL-driver
+ announces the features supported. At the moment this is limited to
+ report the supported layer2 and layer3-protocols. For setting this
+ field the constants ISDN_FEATURE..., declared in isdnif.h have to be
+ used.
+
+ ***CHANGE0.7.1: The line type (1TR6, EDSS1) has to be set.
+
+ unsigned short hl_hdrlen;
+
+ ***CHANGE0.7.4: New field.
+
+ To be preset by the HL-driver, if it supports sk_buff's. The driver
+ should put here the amount of additional space needed in sk_buff's for
+ its internal purposes. Drivers not supporting sk_buff's should
+ initialize this field to 0.
+
+ void (*rcvcallb_skb)(int, int, struct sk_buff *)
+
+ ***CHANGE0.7.4: New field.
+
+ This field will be set by LL. The HL-driver delivers received data-
+ packets by calling this function. Upon calling, the HL-driver must
+ already have its private data pulled off the head of the sk_buff.
+
+ Parameter:
+ int driver-Id
+ int Channel-number locally to the driver. (starting with 0)
+ struct sk_buff * Pointer to sk_buff, containing received data.
+
+ int (*statcallb)(isdn_ctrl*);
+
+ This field will be set by LL. This function has to be called by the
+ HL-driver for signaling status-changes or other events to the LL.
+
+ Parameter:
+ isdn_ctrl*
+
+ The struct isdn_ctrl also defined in isdn_if. The exact meanings of its
+ fields are described together with the descriptions of the possible
+ events. Here is only a short description of the fields:
+
+ driver = driver Id.
+ command = event-type. (one of the constants ISDN_STAT_...)
+ arg = depends on event-type.
+ num = depends on event-type.
+
+ Returnvalue:
+ 0 on success, else -1
+
+ int (*command)(isdn_ctrl*);
+
+ This field has to be preset by the HL-driver. It points to a function,
+ to be called by LL to perform functions like dialing, B-channel
+ setup, etc. The exact meaning of the parameters is described with the
+ descriptions of the possible commands.
+
+ Parameter:
+ isdn_ctrl*
+ driver = driver-Id
+ command = command to perform. (one of the constants ISDN_CMD_...)
+ arg = depends on command.
+ num = depends on command.
+
+ Returnvalue:
+ >=0 on success, else error-code (-ENODEV etc.)
+
+ int (*writebuf_skb)(int, int, int, struct sk_buff *)
+
+ ***CHANGE0.7.4: New field.
+ ***CHANGEI.1.21: New field.
+
+ This field has to be preset by the HL-driver. The given function will
+ be called by the LL for delivering data to be send via B-Channel.
+
+
+ Parameter:
+ int driver-Id ***CHANGE0.7.4: New parameter.
+ int channel-number locally to the HL-driver. (starts with 0)
+ int ack ***ChangeI1.21: New parameter
+ If this is !0, the driver has to signal the delivery
+ by sending an ISDN_STAT_BSENT. If this is 0, the driver
+ MUST NOT send an ISDN_STAT_BSENT.
+ struct sk_buff * Pointer to sk_buff containing data to be send via
+ B-channel.
+
+ Returnvalue:
+ Length of data accepted on success, else error-code (-EINVAL on
+ oversized packets etc.)
+
+ int (*writecmd)(u_char*, int, int, int, int);
+
+ This field has to be preset by the HL-driver. The given function will be
+ called to perform write-requests on /dev/isdnctrl (i.e. sending commands
+ to the card) The data-format is hardware-specific. This function is
+ intended for debugging only. It is not necessary for normal operation
+ and never will be called by the tty-emulation- or network-code. If
+ this function is not supported, the driver has to set NULL here.
+
+ Parameter:
+ u_char* pointer to data.
+ int length of data.
+ int flag: 0 = call from within kernel-space. (HL-driver must use
+ memcpy, may NOT use schedule())
+ 1 = call from user-space. (HL-driver must use
+ memcpy_fromfs, use of schedule() allowed)
+ int driver-Id.
+ int channel-number locally to the HL-driver. (starts with 0)
+
+***CHANGEI1.14: The driver-Id and channel-number are new since this revision.
+
+ Returnvalue:
+ Length of data accepted on success, else error-code (-EINVAL etc.)
+
+ int (*readstat)(u_char*, int, int, int, int);
+
+ This field has to be preset by the HL-driver. The given function will be
+ called to perform read-requests on /dev/isdnctrl (i.e. reading replies
+ from the card) The data-format is hardware-specific. This function is
+ intended for debugging only. It is not necessary for normal operation
+ and never will be called by the tty-emulation- or network-code. If
+ this function is not supported, the driver has to set NULL here.
+
+ Parameter:
+ u_char* pointer to data.
+ int length of data.
+ int flag: 0 = call from within kernel-space. (HL-driver must use
+ memcpy, may NOT use schedule())
+ 1 = call from user-space. (HL-driver must use
+ memcpy_fromfs, use of schedule() allowed)
+ int driver-Id.
+ int channel-number locally to the HL-driver. (starts with 0)
+
+***CHANGEI1.14: The driver-Id and channel-number are new since this revision.
+
+ Returnvalue:
+ Length of data on success, else error-code (-EINVAL etc.)
+
+ char id[20];
+ ***CHANGE0.7: New since this version.
+
+ This string has to be preset by the HL-driver. Its purpose is for
+ identification of the driver by the user. Eg.: it is shown in the
+ status-info of /dev/isdninfo. Furthermore it is used as Id for binding
+ net-interfaces to a specific channel. If a string of length zero is
+ given, upon return, isdn4linux will replace it by a generic name. (line0,
+ line1 etc.) It is recommended to make this string configurable during
+ module-load-time. (copy a global variable to this string.) For doing that,
+ modules 1.2.8 or newer are necessary.
+
+2. Description of the commands, a HL-driver has to support:
+
+ All commands will be performed by calling the function command() described
+ above from within the LL. The field command of the struct-parameter will
+ contain the desired command, the field driver is always set to the
+ appropriate driver-Id.
+
+ Until now, the following commands are defined:
+
+***CHANGEI1.34: The parameter "num" has been replaced by a union "parm" containing
+ the old "num" and a new setup_type struct used for ISDN_CMD_DIAL
+ and ISDN_STAT_ICALL callback.
+
+ ISDN_CMD_IOCTL:
+
+ This command is intended for performing ioctl-calls for configuring
+ hardware or similar purposes (setting port-addresses, loading firmware
+ etc.) For this purpose, in the LL all ioctl-calls with an argument
+ >= IIOCDRVCTL (0x100) will be handed transparently to this
+ function after subtracting 0x100 and placing the result in arg.
+ Example:
+ If a userlevel-program calls ioctl(0x101,...) the function gets
+ called with the field command set to 1.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_IOCTL
+ arg = Original ioctl-cmd - IIOCDRVCTL
+ parm.num = first bytes filled with (unsigned long)arg
+
+ Returnvalue:
+ Depending on driver.
+
+
+ ISDN_CMD_DIAL:
+
+ This command is used to tell the HL-driver it should dial a given
+ number.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_DIAL
+ arg = channel-number locally to the driver. (starting with 0)
+
+ parm.setup.phone = An ASCII-String containing the number to dial.
+ parm.setup.eazmsn = An ASCII-Sting containing the own EAZ or MSN.
+ parm.setup.si1 = The Service-Indicator.
+ parm.setup.si2 = Additional Service-Indicator.
+
+ If the Line has been designed as SPV (a special german
+ feature, meaning semi-leased-line) the phone has to
+ start with an "S".
+ ***CHANGE0.6: In previous versions the EAZ has been given in the
+ highbyte of arg.
+ ***CHANGE0.7.1: New since this version: ServiceIndicator and AddInfo.
+
+ ISDN_CMD_ACCEPTD:
+
+ With this command, the HL-driver is told to accept a D-Channel-setup.
+ (Response to an incoming call)
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_ACCEPTD
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_CMD_ACCEPTB:
+
+ With this command, the HL-driver is told to perform a B-Channel-setup.
+ (after establishing D-Channel-Connection)
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_ACCEPTB
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_CMD_HANGUP:
+
+ With this command, the HL-driver is told to hangup (B-Channel if
+ established first, then D-Channel). This command is also used for
+ actively rejecting an incoming call.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_HANGUP
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_CMD_CLREAZ:
+
+ With this command, the HL-driver is told not to signal incoming
+ calls to the LL.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_CLREAZ
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_CMD_SETEAZ:
+
+ With this command, the HL-driver is told to signal incoming calls for
+ the given EAZs/MSNs to the LL.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_SETEAZ
+ arg = channel-number locally to the driver. (starting with 0)
+ parm.num = ASCII-String, containing the desired EAZ's/MSN's
+ (comma-separated). If an empty String is given, the
+ HL-driver should respond to ALL incoming calls,
+ regardless of the destination-address.
+ ***CHANGE0.6: New since this version the "empty-string"-feature.
+
+ ISDN_CMD_GETEAZ: (currently unused)
+
+ With this command, the HL-driver is told to report the current setting
+ given with ISDN_CMD_SETEAZ.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_GETEAZ
+ arg = channel-number locally to the driver. (starting with 0)
+ parm.num = ASCII-String, containing the current EAZ's/MSN's
+
+ ISDN_CMD_SETSIL: (currently unused)
+
+ With this command, the HL-driver is told to signal only incoming
+ calls with the given Service-Indicators.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_SETSIL
+ arg = channel-number locally to the driver. (starting with 0)
+ parm.num = ASCII-String, containing the desired Service-Indicators.
+
+ ISDN_CMD_GETSIL: (currently unused)
+
+ With this command, the HL-driver is told to return the current
+ Service-Indicators it will respond to.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_SETSIL
+ arg = channel-number locally to the driver. (starting with 0)
+ parm.num = ASCII-String, containing the current Service-Indicators.
+
+ ISDN_CMD_SETL2:
+
+ With this command, the HL-driver is told to select the given Layer-2-
+ protocol. This command is issued by the LL prior to ISDN_CMD_DIAL or
+ ISDN_CMD_ACCEPTD.
+
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_SETL2
+ arg = channel-number locally to the driver. (starting with 0)
+ logical or'ed with (protocol-Id << 8)
+ protocol-Id is one of the constants ISDN_PROTO_L2...
+ parm = unused.
+
+ ISDN_CMD_GETL2: (currently unused)
+
+ With this command, the HL-driver is told to return the current
+ setting of the Layer-2-protocol.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_GETL2
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+ Returnvalue:
+ current protocol-Id (one of the constants ISDN_L2_PROTO)
+
+ ISDN_CMD_SETL3:
+
+ With this command, the HL-driver is told to select the given Layer-3-
+ protocol. This command is issued by the LL prior to ISDN_CMD_DIAL or
+ ISDN_CMD_ACCEPTD.
+
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_SETL3
+ arg = channel-number locally to the driver. (starting with 0)
+ logical or'ed with (protocol-Id << 8)
+ protocol-Id is one of the constants ISDN_PROTO_L3...
+ parm.fax = Pointer to T30_s fax struct. (fax usage only)
+
+ ISDN_CMD_GETL2: (currently unused)
+
+ With this command, the HL-driver is told to return the current
+ setting of the Layer-3-protocol.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_GETL3
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+ Returnvalue:
+ current protocol-Id (one of the constants ISDN_L3_PROTO)
+
+ ISDN_CMD_PROCEED:
+
+ With this command, the HL-driver is told to proceed with a incoming call.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_PROCEED
+ arg = channel-number locally to the driver. (starting with 0)
+ setup.eazmsn= empty string or string send as uus1 in DSS1 with
+ PROCEED message
+
+ ISDN_CMD_ALERT:
+
+ With this command, the HL-driver is told to alert a proceeding call.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_ALERT
+ arg = channel-number locally to the driver. (starting with 0)
+ setup.eazmsn= empty string or string send as uus1 in DSS1 with
+ ALERT message
+
+ ISDN_CMD_REDIR:
+
+ With this command, the HL-driver is told to redirect a call in proceeding
+ or alerting state.
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_REDIR
+ arg = channel-number locally to the driver. (starting with 0)
+ setup.eazmsn= empty string or string send as uus1 in DSS1 protocol
+ setup.screen= screening indicator
+ setup.phone = redirected to party number
+
+ ISDN_CMD_PROT_IO:
+
+ With this call, the LL-driver invokes protocol specific features through
+ the LL.
+ The call is not implicitely bound to a connection.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_CMD_PROT_IO
+ arg = The lower 8 Bits define the addressed protocol as defined
+ in ISDN_PTYPE..., the upper bits are used to differentiate
+ the protocol specific CMD.
+
+ para = protocol and function specific. See isdnif.h for detail.
+
+
+ ISDN_CMD_FAXCMD:
+
+ With this command the HL-driver receives a fax sub-command.
+ For details refer to INTERFACE.fax
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_CMD_FAXCMD
+ arg = channel-number locally to the driver. (starting with 0)
+ parm = unused.
+
+
+3. Description of the events to be signaled by the HL-driver to the LL.
+
+ All status-changes are signaled via calling the previously described
+ function statcallb(). The field command of the struct isdn_cmd has
+ to be set by the HL-driver with the appropriate Status-Id (event-number).
+ The field arg has to be set to the channel-number (locally to the driver,
+ starting with 0) to which this event applies. (Exception: STAVAIL-event)
+
+ Until now, the following Status-Ids are defined:
+
+ ISDN_STAT_AVAIL:
+
+ With this call, the HL-driver signals the availability of new data
+ for readstat(). Used only for debugging-purposes, see description
+ of readstat().
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_STAVAIL
+ arg = length of available data.
+ parm = unused.
+
+ ISDN_STAT_ICALL:
+ ISDN_STAT_ICALLW:
+
+ With this call, the HL-driver signals an incoming call to the LL.
+ If ICALLW is signalled the incoming call is a waiting call without
+ a available B-chan.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_ICALL
+ arg = channel-number, locally to the driver. (starting with 0)
+ para.setup.phone = Callernumber.
+ para.setup.eazmsn = CalledNumber.
+ para.setup.si1 = Service Indicator.
+ para.setup.si2 = Additional Service Indicator.
+ para.setup.plan = octet 3 from Calling party number Information Element.
+ para.setup.screen = octet 3a from Calling party number Information Element.
+
+ Return:
+ 0 = No device matching this call.
+ 1 = At least one device matching this call (RING on ttyI).
+ HL-driver may send ALERTING on the D-channel in this case.
+ 2 = Call will be rejected.
+ 3 = Incoming called party number is currently incomplete.
+ Additional digits are required.
+ Used for signalling with PtP connections.
+ 4 = Call will be held in a proceeding state
+ (HL driver sends PROCEEDING)
+ Used when a user space prog needs time to interpret a call
+ para.setup.eazmsn may be filled with an uus1 message of
+ 30 octets maximum. Empty string if no uus.
+ 5 = Call will be actively deflected to another party
+ Only available in DSS1/EURO protocol
+ para.setup.phone must be set to destination party number
+ para.setup.eazmsn may be filled with an uus1 message of
+ 30 octets maximum. Empty string if no uus.
+ -1 = An error happened. (Invalid parameters for example.)
+ The keypad support now is included in the dial command.
+
+
+ ISDN_STAT_RUN:
+
+ With this call, the HL-driver signals availability of the ISDN-card.
+ (after initializing, loading firmware)
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_RUN
+ arg = unused.
+ parm = unused.
+
+ ISDN_STAT_STOP:
+
+ With this call, the HL-driver signals unavailability of the ISDN-card.
+ (before unloading, while resetting/reconfiguring the card)
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_STOP
+ arg = unused.
+ parm = unused.
+
+ ISDN_STAT_DCONN:
+
+ With this call, the HL-driver signals the successful establishment of
+ a D-Channel-connection. (Response to ISDN_CMD_ACCEPTD or ISDN_CMD_DIAL)
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_DCONN
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_STAT_BCONN:
+
+ With this call, the HL-driver signals the successful establishment of
+ a B-Channel-connection. (Response to ISDN_CMD_ACCEPTB or because the
+ remote-station has initiated establishment)
+
+ The HL driver should call this when the logical l2/l3 protocol
+ connection on top of the physical B-channel is established.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_BCONN
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.num = ASCII-String, containing type of connection (for analog
+ modem only). This will be appended to the CONNECT message
+ e.g. 14400/V.32bis
+
+ ISDN_STAT_DHUP:
+
+ With this call, the HL-driver signals the shutdown of a
+ D-Channel-connection. This could be a response to a prior ISDN_CMD_HANGUP,
+ or caused by a remote-hangup or if the remote-station has actively
+ rejected a call.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_DHUP
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_STAT_BHUP:
+
+ With this call, the HL-driver signals the shutdown of a
+ B-Channel-connection. This could be a response to a prior ISDN_CMD_HANGUP,
+ or caused by a remote-hangup.
+
+ The HL driver should call this as soon as the logical l2/l3 protocol
+ connection on top of the physical B-channel is released.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_BHUP
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_STAT_CINF:
+
+ With this call, the HL-driver delivers charge-unit information to the
+ LL.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_CINF
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.num = ASCII string containing charge-units (digits only).
+
+ ISDN_STAT_LOAD: (currently unused)
+
+ ISDN_STAT_UNLOAD:
+
+ With this call, the HL-driver signals that it will be unloaded now. This
+ tells the LL to release all corresponding data-structures.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_UNLOAD
+ arg = unused.
+ parm = unused.
+
+ ISDN_STAT_BSENT:
+
+ With this call the HL-driver signals the delivery of a data-packet.
+ This callback is used by the network-interfaces only, tty-Emulation
+ does not need this call.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_BSENT
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.length = ***CHANGEI.1.21: New field.
+ the driver has to set this to the original length
+ of the skb at the time of receiving it from the linklevel.
+
+ ISDN_STAT_NODCH:
+
+ With this call, the driver has to respond to a prior ISDN_CMD_DIAL, if
+ no D-Channel is available.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_NODCH
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm = unused.
+
+ ISDN_STAT_ADDCH:
+
+ This call is for HL-drivers, which are unable to check card-type
+ or numbers of supported channels before they have loaded any firmware
+ using ioctl. Those HL-driver simply set the channel-parameter to a
+ minimum channel-number when registering, and later if they know
+ the real amount, perform this call, allocating additional channels.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_ADDCH
+ arg = number of channels to be added.
+ parm = unused.
+
+ ISDN_STAT_CAUSE:
+
+ With this call, the HL-driver delivers CAUSE-messages to the LL.
+ Currently the LL does not use this messages. Their contents is simply
+ logged via kernel-messages. Therefore, currently the format of the
+ messages is completely free. However they should be printable.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_NODCH
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.num = ASCII string containing CAUSE-message.
+
+ ISDN_STAT_DISPLAY:
+
+ With this call, the HL-driver delivers DISPLAY-messages to the LL.
+ Currently the LL does not use this messages.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_DISPLAY
+ arg = channel-number, locally to the driver. (starting with 0)
+ para.display= string containing DISPLAY-message.
+
+ ISDN_STAT_PROT:
+
+ With this call, the HL-driver delivers protocol specific infos to the LL.
+ The call is not implicitely bound to a connection.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_PROT
+ arg = The lower 8 Bits define the addressed protocol as defined
+ in ISDN_PTYPE..., the upper bits are used to differentiate
+ the protocol specific STAT.
+
+ para = protocol and function specific. See isdnif.h for detail.
+
+ ISDN_STAT_DISCH:
+
+ With this call, the HL-driver signals the LL to disable or enable the
+ use of supplied channel and driver.
+ The call may be used to reduce the available number of B-channels after
+ loading the driver. The LL has to ignore a disabled channel when searching
+ for free channels. The HL driver itself never delivers STAT callbacks for
+ disabled channels.
+ The LL returns a nonzero code if the operation was not successful or the
+ selected channel is actually regarded as busy.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_DISCH
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.num[0] = 0 if channel shall be disabled, else enabled.
+
+ ISDN_STAT_L1ERR:
+
+ ***CHANGEI1.21 new status message.
+ A signal can be sent to the linklevel if an Layer1-error results in
+ packet-loss on receive or send. The field errcode of the cmd.parm
+ union describes the error more precisely.
+
+ Parameter:
+ driver = driver-Id
+ command = ISDN_STAT_L1ERR
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm.errcode= ISDN_STAT_L1ERR_SEND: Packet lost while sending.
+ ISDN_STAT_L1ERR_RECV: Packet lost while receiving.
+ ISDN_STAT_FAXIND:
+
+ With this call the HL-driver signals a fax sub-command to the LL.
+ For details refer to INTERFACE.fax
+
+ Parameter:
+ driver = driver-Id.
+ command = ISDN_STAT_FAXIND
+ arg = channel-number, locally to the driver. (starting with 0)
+ parm = unused.
+