Telephony switches - is there anyone out there collecting these?

I've got a few, it depends on what you mean by 'early' I have a couple of the old GPO [1] Modem 2B units; Large metal cases (about 15" square by 6" high) contiaining plug-in PCBs. Modulator and demodualator are discrete transsitors, the control circutry is mostly relays. [1] As in most other conntries, at that time (late 1960's, early 1978's) you had to rent the mdoem from the telephone company, which in the UK was the Post Office (GPO). Some of these modems were actually made by Plessey. A little more recent is the GPO Modem 13, which is a plinth screwed to the bottom of a normal telephone (a type 746 for the UK phone enthusiasts). Said phone has a couple of buttons added to select between voice and data. The plinth contains one PCB with metal-can ICs (maybe custom) and pot core inductors on it. Of course I have a number of 1970's accoustic couplers..... One oddity is the 'barrier box' At one time you had to fit this thing in the RS232 line betwwen your terminal and the (rented) modem. It contained a 50mA (IIRC) fuse in series wtih each signal line and a pair of inverse series zenrs from each line to protective ground (on the modem side of the fuse). The idea was that if something failed in your terminal and an excessive voltage appearsed on the RS232 interface, the fuse would blow before any damage was done to the modem.yes, I have one _somewhere_ I am looking for an old ACU (Automatic Calling Unit) with an RS336 (or is it RS366) interface. I am not planning on using it on a public telephone network, so I don't care about approvals or anything like that. I've never seen one for sale though.... -tony