OPINION OF THE COURT
HANNUM, District Judge.
Appellants, Pasquale Falconio and Wally Berger, were convicted in the United States District Court for the District of New Jersey on multiple counts of conspiracy to import and distribute heroin, violations of the Travel Act, and use of interstate facilities in the furtherance of these conspiracies.
The Government’s proof at trial revealed that the appellants participated in a scheme to smuggle twenty pounds of heroin into the United States from Canada. The scheme was foiled by Royal Canadian Mounted Police working in league with United States authorities.
This appeal alleges numerous grounds for reversal of the convictions below. For the sake of clarity, they can be grouped into two general categories: wiretap violations and trial errors.
I. WIRETAP VIOLATIONS
Appellants contend that damaging evidence introduced at trial and obtained through the interception of telephonic communications (wiretaps) should have been suppressed. Eight reasons are assigned for this contention: the federal wire interception statute, 18 U.S.C. §§ 2510-2520, (Title III Omnibus Crime Control and Safe Streets Act of 1968) is unconstitutional; the authorization of the application for the wiretap by the Attorney General for submission to the Court was defective; the finding of probable cause for the wiretap was insufficient; the finding of necessity for the wiretap was insufficient; the Government failed to minimize non-relevant conversations; the Government failed to secure independent authorization for a pen register; the Government failed to seal promptly the tape recordings of the wiretaps; and the Government failed to comply with the delimiting Manual for the Conduct of Electronic Surveillance promulgated by the Attorney General.
We note at the outset that this Court has held the federal wire interception statute, 18 U.S.C. §§ 2510-2520, (Title III Omnibus Crime Control and Safe Streets Act of 1968) to be constitutional: United States v. Cafero, 473 F.2d 489 (3d Cir. 1972). That holding stands. So far as the finding of necessity for the wiretap, the Government’s minimization of non-relevant conversations, and the Government’s compliance with the delimiting Manual for the Conduct of Electronic Surveillance promulgated by the Attorney General, we affirm the thoughtful and thorough opinion of the district court on these issues. The remaining issues merit discussion.
AUTHORIZATION
The appellants contend that the wiretaps in the instant case were not properly authorized since the Attorney General’s signature was affixed by Sol Lindenbaum, his Executive Assistant. 18 U.S.C. § 2516, the authorization provision, states that the Attorney General, or any Assistant Attorney General specifically designated by the Attorney General, may authorize applications for wiretaps. The recent companion cases of United States v. Giordano, 416 U.S. 505, 94 S.Ct. 1820, 40 L.Ed.2d 341 (1974), and United States v. Chavez, 416 U.S. 562, 94 S.Ct. 1849, 40 L.Ed.2d 380 (1974), examined this provision and set forth guidelines for what constitutes proper authorization.
In Giordano, the Court held that Title III does not permit the authorization of wiretap applications by the Attorney General’s Executive Assistant, and that evidence secured through wiretaps so authorized should be suppressed.
In Chavez, the Court held that misidentifying the Assistant Attorney General as the official authorizing the wiretap application when the Attorney General, himself, had given the approval does not run afoul of Title III, and, therefore, does not require suppression of evidence so obtained.
It is clear from a reading of these cases that the important consideration is not whose name appears on the authorization, and certainly not who signed the authorization. Rather, the important consideration is who actually granted the authorization for the wiretaps.
Turning to the instant case, Sol Lindenbaum, Executive Assistant to the Attorney General, signed the name of the then Attorney General, Richard G. Kleindienst, to the authorization for the wiretap. This act, however, was preceded by a telephone conversation between Lindenbaum and the Attorney General during which the former advised the latter of the contents of a memorandum, recommending that the authorization be granted, prepared by the Assistant Attorney General in charge of the Criminal Division, Henry Peterson. The Attorney General approved the request and directed Mr. Lindebaum to sign the Attorney General’s name to the authorization and to. inform the Assistant Attorney General of the approval. Three days later the Attorney General, himself, entered a file memorandum verifying the verbal authorization he had given to Mr. Lindenbaum.
From these facts, viewed in the light of Giordano and Chavez, we conclude that the authorization here was proper. Crucial to this conclusion is the fact that the Attorney General, fully aware of the facts of the specific case, had personally authorized the wiretap.
PROBABLE CAUSE
The appellants contend that probable cause was lacking for the issuance of the order for the wiretaps. In support of this contention, appellants submit that Berger v. New York, 388 U. S. 41, 87 S.Ct. 1873, 18 L.Ed.2d 1040 (1967); and Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1966) require a more vigorous degree of probable cause for a wiretap than ordinarily required for a search warrant, and that this more vigorous degree of probable cause was lacking. We reject this submission and, in addition, hold that the facts contained in the wiretap applications meet the standards for what constitutes probable cause. Spinelli v. United States, 393 U.S. 410, 89 S.Ct. 584, 21 L.Ed.2d 637 (1969) and Aguilar v. Texas, 378 U.S. 108, 84 S.Ct. 1509, 12 L.Ed.2d 723 (1964).
Probable cause is not a matter of degree. Although Berger and Katz call for extra vigilance in the supervision of electronic eavesdropping, neither case separates probable cause into degrees. Moreover, no special probable cause requirement can be found in the statutory scheme. 18 U.S.C. § 2518(3) (a), (b) and (d). Certainly if a higher degree of probable cause were intended, Congress would have so stated.
PEN REGISTER
The next question presented for resolution is whether a separate order authorizing the use of a pen register is required when a valid order authorizing a simultaneous wiretap has issued ? That is to say, is the authorization for a wiretap sufficient to permit the concomitant implementation of a pen register ?
In the instant case, the Government, after securing an order for a wiretap on Falconio’s telephone, installed both a tape recorder and a pen register. Separate authorization for the pen register was never obtained. Appellants contend that the use of the pen register under these circumstances requires suppression of evidence so obtained. For the reasons which follow we find this contention unpersuasive.
The threshold issue is whether use of a pen register is subject to the provisions of 18 U.S.C. § 2518 which requires authorization for the interception of wire or oral communications? “Intercept” means the “. . . aural acquisition of the contents of any wire or oral communication. . . ” 18 U.S.C. § 2510(4). An “aural acquisition” by definition engages the sense of hearing. Since a pen register does not possess this sense, it is not an interception within the meaning of 18 U.S.C. § 2510(4), and therefore not subject to the authorization provisions of 18 U.S.C. § 2518. United States v. Giordano, 416 U.S. 553, 94 S.Ct. 1845 (1974) (dissenting opinion); United States v. Focarile, 340 F.Supp. 1033 (D.Md.1972), aff’d sub. nom., United States v. Giordano, 469 F.2d 522 (4th Cir. 1972) rev’d on other grounds, 416 U.S. 505, 94 S.Ct. 1820, 40 L.Ed.2d 341 (1974); United States v. Escandar, 319 F.Supp. 295 (S.D.Fla.1970), rev’d on other grounds, 472 F.2d 973 (5th Cir. 1973).
The next issue to be determined is whether 47 U.S.C. § 605 prohibits the use of a pen register. For two reasons we hold that it does not. First, § 605 was amended in 1968 to proscribe the interception of “any radio communication”, this amendment clearly omits telephonic communications. Second, the legislative history of the 1968 Amendment to § 605 reveals that Congress intended to shift all control of electronic surveillance operations to 18 U.S.C. §§ 2510-2520. 1968 U.S.Code Cong. & Admin.News, p. 2178. Thus, having concluded that § 605 does not now control the use of pen registers, we set to one side those cases antecedent to the 1968 amendment which held otherwise and upon which the appellants mistakenly rely. We do not conclude from this analysis that no authorization for the use of pen registers is required. We only conclude that pen registers are neither prohibited by § 605 nor require authorization under § 2518.
Nor must we decide, under the facts of this case, what authorization is necessary when a pen register is used alone. However, when used in conjunction with a wiretap, we conclude that an order permitting interception under Title III for a wiretap provides sufficient authorization for the use of a pen register, and no separate order for the latter is necessary. The reasoning for this conclusion is based on an analysis of the operation of a pen register.
A telephone number is only a symbol for a series of electrical impulses. When a telephone number is dialed from a wiretapped phone, the pen register and the tape recorder are activated simultaneously. Both record the dialing of the phone. And both can be used to determine the telephone number dialed. The pen register records the electrical impulse and automatically translates it back into the number dialed. The tape recorder records the aural manifestation of the electrical impulse which also discloses, if played at a slower speed and examined by an expert, the telephone number dialed. A pen register functions to facilitate the decipherment of the number dialed. It is a mechanical refinement which translates into a different “language” that which has been monitored already. Simply stated, the pen register avoids a mechanical step; it translates automatically and avoids the interpreter.
We hold for the aforementioned reasons that where a valid wiretap order has issued, use of a pen register is comprehended within the terms of that order.
DELAY IN SEALING THE TAPES
Appellants finally contend that the wiretap evidence should not have been admitted because it was not promptly sealed as required by 18 U.S.C. § 2518(8) (a). This section provides that “. . . [¡Immediately upon the expiration of the period of the order, or extensions thereof, such recordings shall be made available to the judge issuing such order and sealed under his directions . . .”.
There is no doubt but that the tapes were not sealed in accordance with the statute. However, it does not follow therefrom that the evidence obtained must be suppressed. As in United States v. Giordano, supra, and United States v. Chavez, supra, we must look to the statutory scheme to determine if Congress has provided that suppression is required for this procedural error.
18 U.S.C. § 2515 provides that wiretap evidence may not be introduced at a criminal trial, “if the disclosure of that information would be in violation of this chapter.” Those violations requiring suppression are provided for in 18 U.S.C. § 2518(10)(a):
“(i) the communication was unlawfully intercepted;
“(ii) the order of authorization or approval under which it was intercepted is insufficient on its face; or
“(iii) the interception was not made in conformity with the order of authorization or approval.”
Paragraphs (ii) and- (iii) are inapplicable because the sealing requirement is statutory and not part of the order. Therefore, if suppression is required, we must find it in paragraph (i). United States v. Giordano, supra, holds that paragraph (i) includes every “failure to satisfy any of those statutory requirements that directly and substantially implement the congressional intention to limit the use of intercept procedures to those situations clearly calling for the employment of this extraordinary investigative device.” 416 U.S. at 527, 94 S.Ct. at 1832.
Viewed in this framework, the issue becomes whether the sealing requirement limits the use of interception procedures ?
The legislative history reveals that the sealing requirement was intended to insure the integrity of the tapes after interception. (Emphasis supplied). 1968 U.S.Code Cong. & Adm. News, p. 2193-2194. The sealing requirement is in nowise “to limit the use of interception procedures ...” Rather, its function is to maintain the integrity of the tapes for evidentiary purposes. We conclude, therefrom, that the sealing requirement is not to limit the use of interception procedures, and, that failure to seal promptly does not render the communication “unlawfully intercepted,” and therefore such failure does not necessitate suppression under the statute.
A second consideration strongly supports this conclusion. 18 U.S.C. § 2518 (8) (a) provides that the “presence of [a] seal . . or a satisfactory explanation for the absence thereof, shall be a prerequisite for the use ... of any [wiretap] . . . ” By this provision Congress has provided for an alternative to the sealing requirement. It would follow from such an alternative that failure to seal the tapes promptly is not such a violation that requires suppression as a matter of law.
In United States v. Poeta, 455 F.2d 117 (2d Cir. 1972), cert. denied, 406 U.S. 948, 92 S.Ct. 2041, 32 L.Ed.2d 337 (1972), police confusion over the applicable law was held a sufficient explanation to overcome the absence of a seal. Here administrative delay may also be a satisfactory explanation. The crucial factor, however, is the integrity of the tapes themselves. This fact must be proved to the trial judge. In the case at bar, after an extensive pre-trial hearing and evidence at trial the court below made a specific finding of fact that the tapes had not been tampered with.
Therefore, all we hold is that where the trial court has found that the integrity of the tapes is pure, a delay in sealing the tapes is not, in and of itself, sufficient reason to suppress the evidence obtained therefrom.
We hasten to add that this holding, of course, does not deprecate the importance of the sealing requirement. Certainly, it should be complied with in all respects. As this case so aptly demonstrates, compliance would have avoided considerable uncertainty and delay.
II. TRIAL ERRORS
In addition to the alleged violations in the gathering of evidence, appellants alleged that the trial court committed reversible error at trial and at sentencing.
At trial, testimony was admitted to the effect that appellant, Falconio, had been previously involved in a separate heroin transaction not the subject matter of this case. Appellant contends that this testimony should not have been admitted since it was evidence only of prior criminal conduct.
Although inadmissible to show a mere propensity or disposition to commit crime, evidence of other crimes is admissible to show one’s intent, plan, scheme, design, or modus operandi. United States v. Todaro, 448 F.2d 64 (3d Cir. 1971), cert. denied, 404 U.S. 1040, 92 S.Ct. 924, 30 L.Ed.2d 732 (1972); United States v. Carter, 401 F.2d 748 (3d Cir. 1968), cert. denied, 393 U.S. 1103, 89 S.Ct. 905, 21 L.Ed.2d 797 (1968); United States v. Stirone, 262 F.2d 571 (3d Cir. 1958), rev’d on other grounds, 361 U.S. 212, 80 S.Ct. 270, 4 L.Ed.2d 252 (1960). Without commenting in detail, the evidence complained of showed an intent on the part of Falconio to sell heroin to one of his co-conspirators, and, further, showed a preexisting business relationship between the two, evidence highly probative of the existence of a conspiracy. Moreover, since the evidence indicated that Falconio owed this co-conspirator $30,000.00 from the previous narcotics transaction, the evidence was probative to show motive for the subsequent narcotics transaction for which he was prosecuted. Thus, there being sufficient grounds for the admission of this evidence, there is no error.
Next appellants allege that the trial court erred when it failed to grant their motion for a mistrial following a question propounded by the Government Attorney and directed to one of its witnesses. Specifically, the Government Attorney asked of the witness, a chemist who was called to testify about the size and quality of average street sales of heroin, whether the narcotic substances in this case were purchased by undercover agents acting for the City of Newark in a drive on narcotics. It is contended that the reference to “drive on narcotics” aroused the passion of the jury against the appellants because of the narcotic problems existent in the Newark area.
Objection to this question was sustained and the jury was instructed to disregard it. In addition, the court made inquiry to determine whether any jurors had been prejudiced by this reference. A review of the record makes clear that an appropriate instruction was given and a mistrial was not required in these circumstances.
Finally, appellant, Falconio, contends that the trial judge should have recused himself before sentencing. In this regard, he filed an affidavit pursuant to 28 U.S.C. § 144.
For a motion to recuse to be granted, the affidavit must allege bias or prejudice from a source other than the Court proceedings in the case, United States v. Grinnell Corp., 384 U.S. 563, 86 S.Ct. 1698, 16 L.Ed.2d 778 (1966); Tynan v. United States, 126 U.S.App.D.C. 206, 376 F.2d 761 (1967). As we said in United States v. Thompson, “The facts [in the affidavit] must show the bias is personal, as opposed to judicial, in nature.” Appellant did not allege in his affidavit that the trial judge’s bias was extrajudicial. An allegation of “judicial” bias is not grounds for a motion to recuse. United States v. Thompson, 483 F.2d 527, 529 (3d Cir. 1973). The motion was properly denied.
The Court finds the remaining contentions in this appeal without merit. The Court also finds that the trial was fair and free of error. Thus, the convictions of the appellants, Falconio and Berger, must be and are affirmed.
. Also known as Falcone, Falcon.
. Title 21 U.S.C. § 952.
. Title 18 U.S.C. § 1952.
. Title 21 U.S.C. § 843(b).
. Evidence used at trial was obtained from wiretaps of two telephones. One telephone was registered to Paul Falcon, appellant. This wiretap commenced on August 28, 1972 and continued until October 16, 1972. The Order for this wiretap, as well as extensions thereof, was signed by The Honorable Frederick B. Lacey of the District Court of New Jersey. The other telephone was registered in Philadelphia, Pennsylvania to Michael De Vito. This wiretap commenced on November 30, 1972 and continued until December 18, 1972. The Honorable John Morgan Davis of the United States District Court for the Eastern District of Pennsylvania executed the Order authorizing this wiretap as well as the subsequent extension on December 15, 1972. Thereafter, appellants filed a motion to suppress the evidence secured through the use of these wiretaps which resulted in a twelve day suppression hearing commencing on August 27, 1973. The trial court denied the motion, 364 F.Supp. 877 (D.N.J.1973), and the trial proceeded.
. AVe include in this reason appellants’ additional reason that the Government failed to advise the District Court of the existence of an informer at the center of the alleged conspiracy.
. Accord, United States v. Whitaker, 474 F.2d 1246 (3d Cir. 1973).
. United States v. Falcone. 364 F.Supp. 877 (D.N.J.1973).
. 416 U.S. at 530, 94 S.Ct. at 1834.
. 416 U.S. at 568, 94 S.Ct. at 1853.
. See, United States v. Chavez, 568 U.S. at 416, 94 S.Ct. at 1853 and in particular Footnote 2.
. Appendix to tire Brief of Appellant, Paul Falconio, at A-l (hereinafter referred to as Appendix).
. Appendix at A-3.
. Appendix at A-3.
. Brief of Appellees at 16.
. E. g., “The need for particularity and evidence of reliability in the showing required when judicial authorization of a search is sought is especially great in the case of eavesdropping.” Berger v. New York, 388 U.S. 41, 56, 87 S.Ct. 1873, 1882, 18 L.Ed.2d 1040.
. “A pen register is a mechanical device attached to a given telephone line and usually installed at a central telephone facility. It records on a paper tape all numbers dialed from that line. It does not identify the telephone numbers from which incoming calls originate, nor does it reveal whether any call, either incoming or outgoing, was completed. Its use does not involve any monitoring of telephone conversations.” United States v. Giordano, 416 U.S. at 549, 94 S.Ct. at 1842 (dissenting opinion).
. The Oxford English Dictionary defines “aural” as : (1) Of or pertaining to the organ of hearing; (2) Received or perceived by the ear.
. United States v. Dote, 371 F.2d 176 (7th Cir. 1966); United States v. Caplan, 255 F.Supp. 805 (E.D.Mich.1966).
. Clearly, the permissibility of its use by law enforcement authorities would depend “entirely on compliance with the constitutional requirements of the Fourth Amendment.” United States v. Giordano, 416 U.S. 553, 94 S.Ct. at 1845 (dissenting opinion).
. See, United States v. King, 478 F.2d 494 (9th Cir. 1973).
. United States v. King, 335 F.Supp. 523, 549 (S.D.Cal.1971).
. Id.
. Nor is the analysis affected by a “touch tone” pdione and use of a pen register equipped with a touch tone decoder. In this regard, see, United States v. Focarile, 340 F.Supp. 1033, 1039 (D.Md.1972).
. Brief of Appellees at page 27.
. “ [In G-iordano] ... we did not go so far as to suggest that every failure to comply fully with any requirement provided in Title III would render the interception of wire or oral communcations ‘unlawful.’ To establish such a rule would be at odds with the statute itself.” United States v. Chavez, 416 U.S. at 574, 94 S.Ct. at 1856.
. Transcript at 770.
. Transcript at 1686 to 1695, especially 1695.