There are a number of TNC's with the PK model series designation, and their ability to do any amount of mail forwarding depends on the model and firmware revision of a given unit. We will discuss three models that are similar in their command structure with regard to packet, the PK-88 and companion model PCB-88, along with at least one version of the PK-232 MBX. If you have a PK-64 that was intended to be used with a Commodore 64, sorry. This model has a rudimentary mail drop that cannot be set up for mail forwarding without some major changes. Therefore, we will not discuss that TNC. There were more than a few versions out there of both of these TNC's, and one could write an entire article about identifying the various firmware revisions and their capabilities! We will concentrate on the most popular and readily available used PK's of the 3 or 4 year-old variety.
There were many firmware upgrades available for both of these TNC's, and some of the expanded capabilities are worth investigating. AEA, despite it's troubles in 1996 and 1997, is still in business under different ownership. Parts, upgrades, and all of the other customary support are back in place. That being said, we'll talk about general forwarding considerations.
First, note that most versions of the PK series do not initiate a connect and forward mail on their own. Your local BBS has to connect up and forward to it, and request a reverse forward. In other words, your TNC may have mail stored, waiting to be forwarded until you get incoming mail. Your BBS sysop may be able to provide a workaround, depending on what the BBS is capable of doing.
Next, the message has to be addressed to a recipient at another BBS. This is done a little differently than some mailboxes and just about all BBS's. Normally when you enter a message into a mailbox or BBS for distant delivery, you include the recipient's home BBS and the hierarchical address of that BBS. Not so in some PK's. The usual BBS send command for such a message might look something like this:
But a your PK might only recognize
S WX9APR @ WZ9APR
If you try to add the usual hierarchical address components, it will ignore it and the rest of your message! The PK will still give you the appropriate mailbox prompts, but the message will hit the bit-bucket. The lack of a complete hierarchical address may be a hindrance to automatic mail delivery by some BBS's. Some BBS's have a list of "known BBS's" and this is no problem - they recognize the BBS call-sign and "fill in the blanks". Others may not do this. You must discuss this with your BBS sysop and see if this will cause a problem for him or her.
Another accommodation you must make is the addition of spaces between the recipient call-sign, the @ symbol, and the recipient's home BBS call-sign. Notice that this appears in the above example. A Send command formatted like this
will not work! Again, the usual mailbox prompts will appear, but the message will wind up in digital "La-La Land". You and your users need to be aware of this fact and will need to adjust your usual habits to accommodate the PK.
Aside from these accommodations, one more will have to be made. Most PK's will not automatically forward a message, even if it is properly addressed. A message intended to be forwarded first has to be "flagged" for forwarding by the operator of the mailbox. This is done with one of the "Sysop Only" commands available only at the console while the operator is locally logged on, "Edit". This command takes the form of the command, followed by the message number, and the letter F (for forward). If message number 5 is to go to a distant BBS, then the command would look like this from the command prompt
Edit 5 F
Simple enough, but it does require that the mailbox Sysop know that the message is there and manually edit the message. If the message is not marked for forwarding, it will just sit there in the mailbox.
There is also another Sysop-only mailbox command, Free. This shows you how much free memory is left in the TNC for mailbox use. This is handy to help keep track of how much space is left when you find your mailbox is heavily used.
Here are the specific PK Commands that must be set for forwarding to take place:
This sets the responses the TNC sends to look like "TAPR" TNC command responses. AEA recommends this for compatibility with some BBS software.
This designates the BBS that will be forwarding to your mailbox. Do not specify an SSID - the TNC will ignore it.
This is present on PK-88's, among others. It is "Packet Lite", a shortened version of the AX.25 protocol. Only some TNC's and almost no BBS's recognize this shortened protocol, it should be shut off.
Naturally, your mailbox has to be on before anybody can use it, and this includes the BBS that you intend to exchange mail with.
MYMAIL (Call-sign with SSID)
This is the call-sign you wish to assign to your mailbox. By convention, it is your call-sign with an SSID of -1. While you can use another version of your call-sign, it should be different than MYCALL (the default).
PK Commands that are optional:
3RDPARTY (ON) or (OFF)
This can be set to on or off, and determines if call-signs other than yourself can send or receive messages with the PK mailbox. 3RDPARTY ON allows anyone to send messages to any call-sign.
KILLONFWD (ON) or (OFF)
Setting this to ON will kill any messages that have been forwarded. If you find that the mailbox is frequently running out of free memory, turn this on. Forwarded messages will be deleted, making room for new messages.
USERS (2 or more)
If you plan on letting the rest of the world use the mailbox (this includes the BBS that is forwarding to you), then this is best set for more than one user. If you are conversing with someone while the BBS tries to start a forwarding session, the BBS will get a "busy" from it's connect request.
Also to be considered are MFROM, MTO and any BUDCALLS that might be in your TNC. These control the manner in which the TNC listens, and of course it has to be able to listen to hear the BBS make a connection. So do keep this in mind.
This will end our sub-series on mail BBS-to-TNC mail forwarding. Please
remember that this is something that requires close cooperation with your
local BBS Sysop, and do follow his or her advice. While we can't cover
all makes and models of TNC's, your Sysop usually can assist with command
parameters and other settings. Good luck with your door-to-door delivery
On to Part 31 - Emergency Operations and Packet Radio
Back to Part 29 - Setting up a Kantronics KPC-3 for mail forwarding
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